A338730 Generating function Sum_{n >= 1} a(n)*x^n = Sum_{k>=1} k*x^(k*(3*k+1)/2)/(1-x^k).

0, 0, 1, 1, 1, 1, 1, 3, 1, 3, 1, 3, 1, 3, 1, 6, 1, 3, 4, 3, 1, 6, 1, 3, 4, 3, 5, 6, 1, 3, 8, 3, 1, 6, 5, 3, 4, 3, 5, 6, 6, 3, 8, 3, 1, 11, 5, 3, 4, 3, 10, 6, 1, 3, 8, 8, 1, 12, 5, 3, 9, 3, 5, 12, 1, 8, 8, 3, 1, 12, 10, 3, 4, 3, 5, 17, 1, 10, 8, 3, 6, 12, 5, 3, 11, 8, 5, 12, 1, 3

Offset

0,8

Comments

The OEIS contains many very similar sequences, but this one was missing.

Links

Seiichi Manyama, Table of n, a(n) for n = 0..10000

Prog

(PARI) my(N=66, x='x+O('x^N)); concat([0, 0], Vec(sum(k=1, N, k*x^(k*(3*k+1)/2)/(1-x^k)))) \\ Seiichi Manyama, Dec 03 2020

Crossrefs

Cf. A001227, A081757, A117277, A330889, A338731, A338732.

Sequence in context: A178220 A334464 A316780 * A104740 A111736 A330889

Adjacent sequences: A338727 A338728 A338729 * A338731 A338732 A338733

Keyword

nonn

Author

N. J. A. Sloane, Dec 02 2020

Status

approved