A292128 Expansion of Product_{k>=1} (1 - 3*x^k).

1, -3, -3, 6, 6, 15, -12, -3, -30, -48, 6, -12, 15, 78, 186, -21, 168, 42, 42, -246, -408, -156, -399, -552, -498, -246, 213, 1248, -318, 1608, 1392, 2508, 1482, 2976, -480, -1011, 1500, -1704, -4296, -4206, -8499, -8652, -7626, -7050, -192, -13008, -480, -2118

Offset

0,2

Links

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

Formula

G.f.: Sum_{i>=0} (-3)^i*x^(i*(i+1)/2)/Product_{j=1..i} (1 - x^j). - Ilya Gutkovskiy, Apr 13 2018

Prog

(PARI) N=66; x='x+O('x^N); Vec(prod(n=1, N, 1-3*x^n))

Crossrefs

Column k=3 of A292131.

Product_{k>=1} (1 - m*x^k): A010815 (m=1), A070877 (m=2), this sequence (m=3).

Cf. A032308, A242587, A292130.

Sequence in context: A240204 A200905 A280510 * A117775 A243307 A021301

Adjacent sequences: A292125 A292126 A292127 * A292129 A292130 A292131

Keyword

sign

Author

Seiichi Manyama, Sep 09 2017

Status

approved