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

0,6

Comments

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

Links

Table of n, a(n) for n=0..50.

Prog

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

Crossrefs

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

Sequence in context: A282504 A022468 A257664 * A050933 A103302 A173288

Adjacent sequences: A181321 A181322 A181323 * A181325 A181326 A181327

Keyword

nonn

Author

Joerg Arndt, Jan 27 2011

Status

approved