A091719 Greatest common divisors of consecutive partition numbers.

1, 1, 1, 1, 1, 1, 1, 1, 2, 6, 14, 7, 1, 1, 1, 11, 33, 11, 35, 1, 33, 6, 1, 5, 1, 2, 14, 2, 11, 1, 2, 11, 69, 1, 1, 1, 1, 11, 55, 21, 21, 11, 11, 1, 1, 2, 2, 7, 1, 11, 11, 33, 21, 7, 7, 1, 1, 2, 220, 1, 1, 11, 1, 1, 2, 2, 1, 1, 5, 1, 3, 1, 1, 1, 44, 7, 1, 1, 2, 2, 1, 11, 77, 11, 11, 1, 1, 1

Offset

0,9

Links

Amiram Eldar, Table of n, a(n) for n = 0..10000

Formula

a(n) = GCD(A000041(n), A000041(n+1));

a(n) = A091717(n+1,n).

Mathematica

a[n_] := GCD[PartitionsP[n], PartitionsP[n + 1]]; Array[a, 100, 0] (* Amiram Eldar, Apr 30 2020 *)
GCD@@#&/@Partition[PartitionsP[Range[0, 90]], 2, 1] (* Harvey P. Dale, Nov 22 2023 *)

Prog

(PARI) a(n) = gcd(numbpart(n), numbpart(n+1)); \\ Michel Marcus, Apr 30 2020

Crossrefs

Cf. A000041, A091717.

Sequence in context: A056592 A349681 A282544 * A058054 A054588 A084106

Adjacent sequences: A091716 A091717 A091718 * A091720 A091721 A091722

Keyword

nonn

Author

Reinhard Zumkeller, Feb 01 2004

Status

approved