A266649 Expansion of Product_{k>=1} 1 - x^(3*k)/(1-x^k).

1, 0, 0, -1, -1, -1, -2, -1, -2, -1, -1, 1, -1, 3, 2, 5, 4, 8, 7, 11, 8, 12, 11, 13, 10, 9, 9, 7, 3, -2, -5, -13, -16, -25, -28, -48, -44, -66, -60, -82, -82, -104, -95, -120, -103, -131, -107, -133, -98, -124, -85, -94, -42, -51, 9, 7, 83, 100, 181, 208, 298

Offset

0,7

Links

Vaclav Kotesovec, Table of n, a(n) for n = 0..5000

Formula

G.f.: Product_{k>=1} (1 - x^k - x^(3*k)) / (1 - x^k).

Mathematica

nmax = 100; CoefficientList[Series[Product[1-x^(3*k)/(1-x^k), {k, 1, nmax}], {x, 0, nmax}], x]

Crossrefs

Cf. A000726, A100405, A266647, A266648, A266650.

Sequence in context: A165022 A030338 A231148 * A159847 A327489 A257886

Adjacent sequences: A266646 A266647 A266648 * A266650 A266651 A266652

Keyword

sign

Author

Vaclav Kotesovec, Jan 02 2016

Status

approved