A181324 G.f. 1/(1-sum(n=1,N,x^(n*(3*n-1)/2))).

1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 8, 11, 16, 22, 29, 38, 50, 68, 93, 126, 169, 225, 302, 407, 550, 742, 997, 1339, 1799, 2421, 3261, 4390, 5906, 7941, 10680, 14371, 19341, 26028, 35017, 47105, 63370, 85261, 114723, 154360, 207679, 279405, 375907, 505759, 680479, 915554, 1231813

Offset: 0

Author

Joerg Arndt, Jan 27 2011

Keywords

• nonn

Comments

Number of compositions into positive pentagonal numbers (A000326). [Joerg Arndt, Jun 10 2011]

Crossrefs

A023361 ( g.f. 1/(1-sum(n=1,N,x^(n*(n+1)/2))) ).

Programs

PARI

N=99; x='x+O('x^N);
Vec(1/(1-sum(n=1,N,x^(n*(3*n-1)/2)))) /* show terms */