A338731 Generating function Sum_{n >= 0} a(n)*x^n = Sum_{k>=1} x^(k*(3*k+1)/2)/(1-x^k).

0, 0, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 2, 1, 3, 1, 2, 2, 2, 1, 3, 1, 2, 2, 2, 2, 3, 1, 2, 3, 2, 1, 3, 2, 2, 2, 2, 2, 3, 2, 2, 3, 2, 1, 4, 2, 2, 2, 2, 3, 3, 1, 2, 3, 3, 1, 4, 2, 2, 3, 2, 2, 4, 1, 3, 3, 2, 1, 4, 3, 2, 2, 2, 2, 5, 1, 3, 3, 2, 2, 4, 2, 2, 3, 3, 2, 4, 1, 2, 4, 3, 1

Offset: 0

Author

N. J. A. Sloane, Dec 02 2020

Keywords

• nonn

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

Crossrefs

Cf. A001227, A081757, A117277, A330889, A338730, A338732.

Programs

PARI

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