A305355 Expansion of Product_{k>=1} (1 - x^(k*(3*k-1)/2)).

1, -1, 0, 0, 0, -1, 1, 0, 0, 0, 0, 0, -1, 1, 0, 0, 0, 1, -1, 0, 0, 0, -1, 1, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 1, -2, 1, 0, 0, -1, 2, -1, 0, 0, 0, 0, 0, 1, -1, 0, 0, -1, 0, 1, 0, 0, 1, 0, -1, 0, 0, 0, -1, 2, -1, 0, 0, 0, -1, 0, 0, 1, 0, 1, 0, 0, -1, 0, -1, 1, 0, 0, 1

Offset

0,36

Links

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

Wikipedia, Pentagonal number

Maple

seq(coeff(series(mul(1-x^(k*(3*k-1)/2), k=1..n), x, n+1), x, n), n=0..140); # Muniru A Asiru, May 31 2018

Crossrefs

Product_{k>=1} (1 - x^(k*((m-2)*k-(m-4))/2)): A292518 (m=3), A276516 (m=4), this sequence (m=5).

Cf. A000326, A218379, A218380.

Sequence in context: A107628 A268389 A288969 * A218380 A152815 A115296

Adjacent sequences: A305352 A305353 A305354 * A305356 A305357 A305358

Keyword

sign

Author

Seiichi Manyama, May 31 2018

Status

approved