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600 (number)

From Wikipedia, the free encyclopedia
(Redirected from 691 (number))
599 600 601
Cardinalsix hundred
Ordinal600th
(six hundredth)
Numeral systemsescentesimal
Factorization23 × 3 × 52
Divisors1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 20, 24, 25, 30, 40, 50, 60, 75, 100, 120, 150, 200, 300, 600
Greek numeralΧ´
Roman numeralDC, dc
Binary10010110002
Ternary2110203
Senary24406
Octal11308
Duodecimal42012
Hexadecimal25816
ArmenianՈ
Hebrewת"ר / ם
Babylonian cuneiform𒌋
Egyptian hieroglyph𓍧

600 (six hundred) is the natural number following 599 and preceding 601.

Mathematical properties

[edit]

Six hundred is a composite number, an abundant number, a pronic number,[1] a Harshad number and a largely composite number.[2]

Credit

[edit]

In the United States, a credit score of 600 or below is considered poor, limiting available credit at a normal interest rate

Integers from 601 to 699

[edit]

600s

[edit]

601

[edit]

601 is a prime number and a centered pentagonal number.[3]

602

[edit]

602 = 2 × 7 × 43. It is a nontotient. There are 602 cubes of edge length 1 required to make a hollow cube of edge length 11[4]

603

[edit]

603 = 32 × 67. It is a Harshad number and a Riordan number.[5]

604

[edit]

604 = 22 × 151. It is a nontotient and the totient sum for first 44 integers.

605

[edit]

605 = 5 × 112. It is a Harshad number and the sum of the nontriangular numbers between the two successive triangular numbers 55 and 66.[6] There are 605 non-isomorphic set-systems of weight 9.[7]

606

[edit]

606 = 2 × 3 × 101. It is a sphenic number, an admirable number[8] and the sum of six consecutive primes (89 + 97 + 101 + 103 + 107 + 109).

606 is one of the numbers associated with Christ - ΧϚʹ - see the Greek numerals Isopsephy and the reason why other numbers siblings with this one are Beast's numbers.

607

[edit]

607 is a prime number, a balanced prime,[9] a Mersenne prime exponent, the sum of three consecutive primes (197 + 199 + 211), a zero of Mertens function and a strictly non-palindromic number[10]

608

[edit]

608 = 25 × 19. It is a nontotient, a happy number, and a zero of the Mertens function. There are 608 regions formed by drawing the line segments connecting any two of the perimeter points of a 3 times 4 grid of squares[11]

609

[edit]

609 = 3 × 7 × 29. It is a sphenic number and a strobogrammatic number.[12]

610s

[edit]

610

[edit]

610 =2 × 5 × 61. It is a deficient number, a Markov number, a sphenic number, and a member of the Fibonacci sequence.

611

[edit]

611 = 13 × 47. It is the sum of the three standard board sizes in Go (92 + 132 + 192).

The 611th tribonacci number is prime.[13]

612

[edit]

612 = 22 × 32 × 17. It is a Harshad number, an untouchable number, and a Zuckerman number (sequence A007602 in the OEIS).

613

[edit]

614

[edit]

614 = 2 × 307. It is a nontotient and a 2-Knödel number.

According to Rabbi Emil Fackenheim, the number of Commandments in Judaism should be 614 rather than the traditional 613.

615

[edit]

615 = 3 × 5 × 41. It is a sphenic number.

616

[edit]

616 = 23 × 7 × 11. It is a Padovan number and a balanced number.[14]

616 is an alternative value for the Number of the Beast (more commonly accepted to be 666)

617

[edit]

617 is a prime number, a Chen prime, an Eisenstein prime with no imaginary part, a super-prime,[15] an index of prime Lucas number,[16] and the sum of five consecutive primes (109 + 113 + 127 + 131 + 137).

There are 617 compositions of 17 into distinct parts.[17]

618

[edit]

618 = 2 × 3 × 103. It is a sphenic number and an admirable number.[8]

619

[edit]

619 is a prime number, a strobogrammatic prime,[18] and an alternating factorial.[19]

620s

[edit]

620

[edit]

620 = 22 × 5 × 31. It is the sum of four consecutive primes (149 + 151 + 157 + 163) and the sum of eight consecutive primes (61 + 67 + 71 + 73 + 79 + 83 + 89 + 97).

The sum of the first 620 primes is itself prime.[20]

621

[edit]

621 = 33 × 23. It is a Harshad number, and it is the discriminant of a totally real cubic field.[21]

622

[edit]

622 = 2 × 311. It isa nontotient and a fine number (sequence A000957 in the OEIS).

623

[edit]

623 = 7 × 89. There are 623 partitions of 23 into an even number of parts.[22]

624

[edit]

624 = 24 × 3 × 13. It is a Harshad number, a Zuckerman number and the sum of a twin prime pair (311 + 313).

624=J4(5).[23]

625

[edit]

625 = 252 = 54 It is a centered octagonal number,[24] a 1-automorphic number, a Friedman number because 625 = 562,[25] the sum of seven consecutive primes (73 + 79 + 83 + 89 + 97 + 101 + 103).

It is one of the two three-digit numbers that when squared or raised to a higher power that end in the same three digits, the other being 376.

626

[edit]

626 = 2 × 313. It is a nontotient and a 2-Knödel number,

627

[edit]

627 = 3 × 11 × 19. It is a sphenic number and a Smith number[26] There are 627 integer partitions of 20. [27]

628

[edit]

628 = 22 × 157. It is a nontotient and the totient sum for first 45 integers.

629

[edit]

629 = 17 × 37. It is a highly cototient number[28] and a Harshad number. There are 629 diagonals in a 37-gon.[29]

630s

[edit]

630

[edit]

630 = 2 × 32 × 5 × 7. It is a hexagonal number,[30] a sparsely totient number,[31] a Harshad number, a balanced number,[32] a largely composite number,[2] the 35th triangular number,[33] and the sum of six consecutive primes (97 + 101 + 103 + 107 + 109 + 113).

631

[edit]

631 is a prime number, a Cuban prime, a Lucky prime a Chen prime, a centered triangular number,[34] a centered hexagonal number,[35] and a lazy caterer number (sequence A000124 in the OEIS).

632

[edit]

632 = 23 × 79. It is a refactorable number. There are 632 13-bead necklaces with 2 colors[36]

633

[edit]

633 = 3 × 211. It is a Blum integer and the sum of three consecutive primes (199 + 211 + 223).

634

[edit]

634 = 2 × 317. It is a nontotient and a Smith number.[26]

635

[edit]

635 = 5 × 127. It is a zero of the Mertens function and the sum of nine consecutive primes (53 + 59 + 61 + 67 + 71 + 73 + 79 + 83 + 89).

There are 635 compositions of 13 into pairwise relatively prime parts.[37] 635/504∛2[38]

636

[edit]

636 = 22 × 3 × 53. It is a Smith number,[26] a zero of the Mertens function, and the sum of ten consecutive primes (43 + 47 + 53 + 59 + 61 + 67 + 71 + 73 + 79 + 83).

637

[edit]

637 = 72 × 13. It is a decagonal number[39] and a zero of the Mertens function.

638

[edit]

638 = 2 × 11 × 29. It is a sphenic number, a nontotient, a centered heptagonal number,[40] and the sum of four consecutive primes (151 + 157 + 163 + 167).

639

[edit]

639 = 32 × 71. It is the sum of the first twenty primes.

640

[edit]

640

[edit]

640 = 27 × 5. It is a Harshad number, a refactorable number, and a hexadecagonal number[41]

There are 640 1's in all partitions of 24 into odd parts,[42] There are 640 acres in a square mile.

641

[edit]

641 is a prime number, a Sophie Germain prime,[43] a Chen prime, an Eisenstein prime with no imaginary part and a Proth prime. It is a factor of 4294967297, the smallest nonprime Fermat number.

642

[edit]

642 = 2 × 3 × 107. It is a sphenic number and an admirable number.[8]

642= 14 + 24 + 54,[44] making 642 a counterexample of

643

[edit]

643 is a prime number.

644

[edit]

644 = 22 × 7 × 23. It is a nontotient, a Perrin number,[45] a Harshad number, an admirable number[8] and a common umask.

645

[edit]

645 = 3 × 5 × 43. It is a sphenic number, an octagonal number, a Smith number,[26] a Harshad number and a Fermat pseudoprime to base 2.[46]

646

[edit]

646 = 2 × 17 × 19. It is a sphenic number

There are 646 permutations of length 7 without rising or falling successions.[47]

647

[edit]

647 is a Chen prime, an Eisenstein prime with no imaginary part, and the sum of five consecutive primes (113 + 127 + 131 + 137 + 139).

3647 - 2647 is prime[48]

648

[edit]

648 = 23 × 34. It is a Harshad number and an Achilles number.

649

[edit]

649 = 11 × 59. It is a Blum integer.

650s

[edit]

650

[edit]

650 = 2 × 52 × 13. It is a primitive abundant number,[49] a square pyramidal number,[50] a pronic number,[1] a nontotient an admirable number,[8] and the totient sum for first 46 integers.

651

[edit]

651 = 3 × 7 × 31. It is a sphenic number, a pentagonal number,[51] and a nonagonal number.[52]

652

[edit]

652 = 22 × 163. It is the maximal number of regions by drawing 26 circles[53]

653

[edit]

653 is a prime number, a Sophie Germain prime,[43] a balanced prime,[9] a Chen prime, and an Eisenstein prime with no imaginary part.

654

[edit]

654 = 2 × 3 × 109. It is a sphenic number, a nontotient, a Smith number,[26] and an admirable number[8]

655

[edit]

655 = 5 × 131. There are 655 toothpicks after 20 stages in a three-dimensional grid.[54]

656

[edit]

656 = 24 × 41 = ,[55]

In Judaism, Jerusalem is mentioned in the Hebrew Bible and the Old Testament a total of 656 times.

657

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657 = 32 × 73. It is the largest known number not of the form a2+s with s a semiprime

658

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658 = 2 × 7 × 47. It is a sphenic number and an untouchable number.

659

[edit]

659 is a prime number, a Sophie Germain prime,[43] a Chen prime an Eisenstein prime with no imaginary part, strictly non-palindromic number,[10] highly cototient number,[28] and the sum of seven consecutive primes (79 + 83 + 89 + 97 + 101 + 103 + 107).

Mertens function sets a new low of 10 at 659 which stands until 661.

660s

[edit]

660

[edit]

660 = 22 × 3 × 5 × 11. It is a sparsely totient number,[31] a Harshad number, and a largely composite number.[2] It is the sum of four consecutive primes (157 + 163 + 167 + 173), the sum of six consecutive primes (101 + 103 + 107 + 109 + 113 + 127), and the sum of eight consecutive primes (67 + 71 + 73 + 79 + 83 + 89 + 97 + 101). It is the sum of 11th row when writing the natural numbers as a triangle.[56]

661

[edit]

661 is:

  • a prime number
  • the sum of three consecutive primes (211 + 223 + 227)
  • a Pentagram number of the form
  • a Hexagram number of the form i.e. a star number

Mertens function sets new low of 11 at 661 which stands until 665.

662

[edit]

662 = 2 × 331. It is a nontotient and a member of Mian–Chowla sequence.[57]

663

[edit]

663 = 3 × 13 × 17. It is a sphenic number and a Smith number.[26]

664

[edit]

664 = 23 × 83. It is a refactorable number.

There are 664 knapsack partitions of 33.[58]

665

[edit]

665 = 5 × 7 × 19. It is a sphenic number.

There are 665 diagonals in a 38-gon.[29] Mertens function sets new low of 12 at 665 which stands until 1105.

666

[edit]

667

[edit]

667 = 23 × 29. It is a lazy caterer number.[59]

668

[edit]

668 = 22 × 167. It is a nontotient.

669

[edit]

669 = 3 × 223. It is a Blum integer.

670s

[edit]

670

[edit]

670 = 2 × 5 × 67. It is a sphenic number, an octahedral number,[60] and a nontotient.

671

[edit]

671 = 11 × 61.

The magic constant of n×n normal magic square and n-queens problem for n = 11 is 671.

672

[edit]

672 = 25 × 3 × 7. It is a harmonic divisor number,[61] a Zuckerman number, an admirable number,[8] a largely composite number,[2] and a triperfect number.

673

[edit]

673 is a prime number, a lucky prime, and a Proth prime.[62]

674

[edit]

674 = 2 × 337. It is a nontotient and a 2-Knödel number.

675

[edit]

675 = 33 × 52. It is an Achilles number.

676

[edit]

676 = 22 × 132 = 262. It is a palindromic square.

677

[edit]

677 is a prime number, a Chen prime, and an Eisenstein prime with no imaginary part.

There are 677 non-isomorphic self-dual multiset partitions of weight 10.[63]

678

[edit]

678 = 2 × 3 × 113. It is a sphenic number, a nontotient, and an admirable number.[8]

There are 678 surface points of an octahedron with side length 13.[64]

679

[edit]

679 = 7 × 97. It is the sum of three consecutive primes (223 + 227 + 229) and the sum of nine consecutive primes (59 + 61 + 67 + 71 + 73 + 79 + 83 + 89 + 97). It is the smallest number of multiplicative persistence 5.[65]

680s

[edit]

680

[edit]

680 = 23 × 5 × 17. It is a tetrahedral number[66] and a nontotient.

681

[edit]

681 = 3 × 227. It is a centered pentagonal number.[3]

682

[edit]

682 = 2 × 11 × 31. It is a sphenic number, the sum of four consecutive primes (163 + 167 + 173 + 179), and the sum of ten consecutive primes (47 + 53 + 59 + 61 + 67 + 71 + 73 + 79 + 83 + 89).

Solving the Norwegian puzzle strikketoy[67] requires 682 moves.

683

[edit]

683 is a prime number, a Sophie Germain prime,[43] a Chen prime, an Eisenstein prime with no imaginary part, a Wagstaff prime,[68] and the sum of five consecutive primes (127 + 131 + 137 + 139 + 149).

684

[edit]

684 = 22 × 32 × 19. It is a Harshad number.

There are 684 graphical forest partitions of 32.[69]

685

[edit]

685 = 5 × 137 It is a centered square number.[70]

686

[edit]

686 = 2 × 73.It is a nontotient. There are 686 multigraphs on infinite set of nodes with 7 edges.[71]

687

[edit]

687 = 3 × 229. It is a D-number.[72] Mars takes 687 days to orbit around the sun.

688

[edit]

688 = 24 × 43. It is a 2-automorphic number,[73] and a Friedman number since 688 = 8 × 86.[25]

689

[edit]

689 = 13 × 53. It is a Strobogrammatic number,[74] the sum of three consecutive primes (227 + 229 + 233), and the sum of seven consecutive primes (83 + 89 + 97 + 101 + 103 + 107 + 109).

690s

[edit]

690

[edit]

690 = 2 × 3 × 5 × 23. It is a sparsely totient number,[31] a Smith number,[26] a Harshad number, and the sum of six consecutive primes (103 + 107 + 109 + 113 + 127 + 131).

691

[edit]

691 is a prime number.

Ramanujan's tau function τ and the divisor function σ11 are related by the congruence τ(n) ≡ σ11(n) (mod 691).

Negative 691 is the numerator of the Bernoulli number B12 = -691/2730. In number theory, 691 is a "marker" (similar to the radioactive markers in biology): whenever it appears in a computation, it is a sign that Bernoulli numbers are involved.

692

[edit]

692 = 22 × 173. There are 692 partitions of 48 into powers of 2.[75]

693

[edit]

693 = 32 × 7 × 11.

693 appears as the first three digits after the decimal point in the decimal form for the natural logarithm of 2. To 10 digits, this number is 0.6931471805.[76] As a result, if an event has a constant probability of 0.1% of occurring, 693 is the smallest number of trials that must be performed for there to be at least a 50% chance that the event occurs at least once. More generally, for any probability p, the probability that the event occurs at least once in a sample of n items, assuming the items are independent, is given by the following formula:[citation needed]

1 − (1 − p)n

For p = 10−3 = 0.001, plugging in n = 692 gives, to four decimal places, 0.4996, while n = 693 yields 0.5001.[citation needed]

693 is a palindrome in binary in bases 32, 62, 76, 98, 230, and 692.[citation needed]

694

[edit]

694 = 2 × 347. It is a centered triangular number,[34] a nontotient, and the smallest pandigital number in base 5.[77]

695

[edit]

695 = 5 × 139.

695!! + 2 is prime.[78]

696

[edit]

696 = 23 × 3 × 29. It is the totient sum for first 47 integers, the sum of a twin prime pair (347 + 349), and the sum of eight consecutive primes (71 + 73 + 79 + 83 + 89 + 97 + 101 + 103). There are 696 trails of length 9 on honeycomb lattice.[79]

697

[edit]

697 = 17 × 41. It is a cake number.The US state of Colorado has 697 sides.[80]

698

[edit]

698 = 2 × 349. It is a nontotient and the sum of squares of two primes.[81]

699

[edit]

699 = 3 × 233. It is a D-number.[72]

References

[edit]
  1. 1 2 Sloane, N. J. A. (ed.). "Sequence A002378 (Oblong (or promic, pronic, or heteromecic) numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  2. 1 2 3 4 Sloane, N. J. A. (ed.). "Sequence A067128 (Ramanujan's largely composite numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  3. 1 2 Sloane, N. J. A. (ed.). "Sequence A005891 (Centered pentagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  4. "A005897 - OEIS". oeis.org. Retrieved 2026-06-14.
  5. "A005043 - OEIS". oeis.org. Retrieved 2026-06-14.
  6. "A006002 - OEIS". oeis.org. Retrieved 2026-06-14.
  7. "A283877 - OEIS". oeis.org. Retrieved 2026-06-14.
  8. 1 2 3 4 5 6 7 8 "A111592 - OEIS". oeis.org. Retrieved 2026-06-14.
  9. 1 2 Sloane, N. J. A. (ed.). "Sequence A006562 (Balanced primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  10. 1 2 Sloane, N. J. A. (ed.). "Sequence A016038 (Strictly non-palindromic numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  11. Sloane, N. J. A. (ed.). "Sequence A331452 (Triangle read by rows: T(n,m) (n >= m >= 1) = number of regions (or cells) formed by drawing the line segments connecting any two of the 2*(m+n) perimeter points of an m X n grid of squares)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  12. Sloane, N. J. A. (ed.). "Sequence A000787 (Strobogrammatic numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  13. "A232543 - OEIS". oeis.org. Retrieved 2026-06-14.
  14. Sloane, N. J. A. (ed.). "Sequence A020492 (Balanced numbers: numbers k such that phi(k) (A000010) divides sigma(k) (A000203))". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  15. "A006450 - OEIS". oeis.org. Retrieved 2026-06-14.
  16. Sloane, N. J. A. (ed.). "Sequence A001606 (Indices of prime Lucas numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  17. Sloane, N. J. A. (ed.). "Sequence A032020 (Number of compositions (ordered partitions) of n into distinct parts)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-24.
  18. Sloane, N. J. A. (ed.). "Sequence A007597 (Strobogrammatic primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  19. Sloane, N. J. A. (ed.). "Sequence A005165 (Alternating factorials)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  20. (sequence A013916 in the OEIS)
  21. Sloane, N. J. A. (ed.). "Sequence A006832 (Discriminants of totally real cubic fields)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  22. Sloane, N. J. A. (ed.). "Sequence A027187 (Number of partitions of n into an even number of parts)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  23. Sloane, N. J. A. (ed.). "Sequence A059377 (Jordan function J_4(n))". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  24. Sloane, N. J. A. (ed.). "Sequence A016754 (Odd squares: a(n) = (2n+1)^2. Also centered octagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  25. 1 2 Sloane, N. J. A. (ed.). "Sequence A036057 (Friedman numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  26. 1 2 3 4 5 6 7 Sloane, N. J. A. (ed.). "Sequence A006753 (Smith numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  27. Sloane, N. J. A. (ed.). "Sequence A000041 (a(n) = number of partitions of n)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  28. 1 2 Sloane, N. J. A. (ed.). "Sequence A100827 (Highly cototient numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  29. 1 2 Sloane, N. J. A. (ed.). "Sequence A000096 (a(n) = n*(n+3)/2)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  30. Sloane, N. J. A. (ed.). "Sequence A000384 (Hexagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  31. 1 2 3 Sloane, N. J. A. (ed.). "Sequence A036913 (Sparsely totient numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  32. Sloane, N. J. A. (ed.). "Sequence A020492 (Balanced numbers: numbers k such that phi(k) (A000010) divides sigma(k) (A000203))". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  33. "A000217 - OEIS". oeis.org. Retrieved 2024-11-29.
  34. 1 2 Sloane, N. J. A. (ed.). "Sequence A005448 (Centered triangular numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  35. Sloane, N. J. A. (ed.). "Sequence A003215 (Hex (or centered hexagonal) numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  36. Sloane, N. J. A. (ed.). "Sequence A000031 (Number of n-bead necklaces with 2 colors when turning over is not allowed; also number of output sequences from a simple n-stage cycling shift register; also number of binary irreducible polynomials whose degree divides n)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  37. Sloane, N. J. A. (ed.). "Sequence A101268 (Number of compositions of n into pairwise relatively prime parts)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-31.
  38. "Continued Fractions and Characteristic Recurrences". Math Pages.
  39. Sloane, N. J. A. (ed.). "Sequence A001107 (10-gonal (or decagonal) numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  40. Sloane, N. J. A. (ed.). "Sequence A069099 (Centered heptagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  41. Sloane, N. J. A. (ed.). "Sequence A051868 (16-gonal (or hexadecagonal) numbers: a(n) = n*(7*n-6))". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  42. Sloane, N. J. A. (ed.). "Sequence A036469 (Partial sums of A000009 (partitions into distinct parts))". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  43. 1 2 3 4 Sloane, N. J. A. (ed.). "Sequence A005384 (Sophie Germain primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  44. Sloane, N. J. A. (ed.). "Sequence A074501 (a(n) = 1^n + 2^n + 5^n)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-31.
  45. "Sloane's A001608 : Perrin sequence". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  46. Sloane, N. J. A. (ed.). "Sequence A001567 (Fermat pseudoprimes to base 2)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  47. Sloane, N. J. A. (ed.). "Sequence A002464 (Hertzsprung's problem: ways to arrange n non-attacking kings on an n X n board, with 1 in each row and column. Also number of permutations of length n without rising or falling successions)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  48. Sloane, N. J. A. (ed.). "Sequence A057468 (Numbers k such that 3^k - 2^k is prime)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  49. Sloane, N. J. A. (ed.). "Sequence A071395 (Primitive abundant numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  50. Sloane, N. J. A. (ed.). "Sequence A000330 (Square pyramidal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  51. Sloane, N. J. A. (ed.). "Sequence A000326 (Pentagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  52. Sloane, N. J. A. (ed.). "Sequence A001106 (9-gonal (or enneagonal or nonagonal) numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  53. Sloane, N. J. A. (ed.). "Sequence A014206 (a(n) = n^2 + n + 2)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  54. Sloane, N. J. A. (ed.). "Sequence A160160 (Toothpick sequence in the three-dimensional grid)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  55. Sloane, N. J. A. (ed.). "Sequence A002379 (a(n) = floor(3^n / 2^n))". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  56. Sloane, N. J. A. (ed.). "Sequence A027480 (a(n) = n*(n+1)*(n+2)/2)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  57. Sloane, N. J. A. (ed.). "Sequence A005282 (Mian-Chowla sequence)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  58. Sloane, N. J. A. (ed.). "Sequence A108917 (Number of knapsack partitions of n)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  59. "A000124 - OEIS". oeis.org. Retrieved 2026-07-02.
  60. Sloane, N. J. A. (ed.). "Sequence A005900 (Octahedral numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  61. Sloane, N. J. A. (ed.). "Sequence A001599 (Harmonic or Ore numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  62. Sloane, N. J. A. (ed.). "Sequence A080076 (Proth primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  63. Sloane, N. J. A. (ed.). "Sequence A316983 (Number of non-isomorphic self-dual multiset partitions of weight n)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  64. Sloane, N. J. A. (ed.). "Sequence A005899 (Number of points on surface of octahedron with side n)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-31.
  65. Sloane, N. J. A. (ed.). "Sequence A003001 (Smallest number of multiplicative persistence n)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-31.
  66. Sloane, N. J. A. (ed.). "Sequence A000292 (Tetrahedral numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  67. Sloane, N. J. A. (ed.). "Sequence A000975 (Lichtenberg sequence)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-31.
  68. Sloane, N. J. A. (ed.). "Sequence A000979 (Wagstaff primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  69. Sloane, N. J. A. (ed.). "Sequence A000070 (a(n) = Sum_{k=0..n} p(k) where p(k) = number of partitions of k (A000041))". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-31.
  70. Sloane, N. J. A. (ed.). "Sequence A001844 (Centered square numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
  71. Sloane, N. J. A. (ed.). "Sequence A050535 (Number of multigraphs on infinite set of nodes with n edges)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-31.
  72. 1 2 Sloane, N. J. A. (ed.). "Sequence A033553 (3-Knödel numbers or D-numbers: numbers n > 3 such that n divides k^(n-2)-k for all k with gcd(k, n) = 1)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-31.
  73. Sloane, N. J. A. (ed.). "Sequence A030984 (2-automorphic numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2021-09-01.
  74. Sloane, N. J. A. (ed.). "Sequence A000787 (Strobogrammatic numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  75. Sloane, N. J. A. (ed.). "Sequence A000123 (Number of binary partitions: number of partitions of 2n into powers of 2)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-31.
  76. Weisstein, Eric W. "Natural Logarithm of 2". mathworld.wolfram.com. Retrieved 2026-07-29.
  77. Sloane, N. J. A. (ed.). "Sequence A049363 (a(1) = 1; for n > 1, smallest digitally balanced number in base n)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  78. Sloane, N. J. A. (ed.). "Sequence A076185 (Numbers n such that n!! + 2 is prime)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-31.
  79. Sloane, N. J. A. (ed.). "Sequence A006851 (Trails of length n on honeycomb lattice)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-05-18.
  80. "Colorado is a rectangle? Think again". 23 January 2023.
  81. Sloane, N. J. A. (ed.). "Sequence A045636 (Numbers of the form p^2 + q^2, with p and q primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.