A350737 Expansion of Sum_{k>=0} (-1)^k * x^(k*(3*k+1)/2) / Product_{j=1..k} (1-x^j).

1, 0, -1, -1, -1, -1, -1, 0, 0, 1, 1, 2, 2, 3, 3, 3, 3, 3, 2, 2, 1, 0, -1, -2, -4, -5, -6, -8, -9, -10, -11, -12, -12, -13, -12, -12, -11, -10, -7, -6, -3, 0, 4, 7, 12, 15, 21, 25, 30, 34, 40, 43, 48, 51, 55, 56, 59, 59, 60, 58, 56, 52, 49, 42, 35, 26, 17, 5, -7, -21, -36, -52, -69, -87, -105, -124, -144, -163

Offset

0,12

Links

Table of n, a(n) for n=0..77.

Prog

(PARI) my(N=99, x='x+O('x^N)); Vec(sum(k=0, N, (-1)^k*x^(k*(3*k+1)/2)/prod(j=1, k, 1-x^j)))

Crossrefs

Cf. A039924, A237979, A350310, A350738.

Sequence in context: A338687 A331677 A304733 * A360391 A165024 A300402

Adjacent sequences: A350734 A350735 A350736 * A350738 A350739 A350740

Keyword

sign

Author

Seiichi Manyama, Jan 12 2022

Status

approved