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A307520
Expansion of Product_{k>=1} ((1 - x)^k - x^k)/((1 - x)^k + x^k).
2
1, -2, -2, -2, 0, 6, 18, 38, 68, 108, 148, 148, -2, -552, -2004, -5280, -11960, -24590, -46990, -84254, -141476, -218654, -295794, -295374, 3540, 1148110, 4378918, 12332318, 30327568, 68633710, 146303026, 297349758, 580052778, 1089382158, 1969425038, 3413378318, 5614375970
OFFSET
0,2
FORMULA
G.f.: theta_4(x/(1 - x)), where theta_4() is the Jacobi theta function.
MATHEMATICA
m = 36; CoefficientList[Series[Product[((1 - x)^k - x^k)/((1 - x)^k + x^k), {k, 1, m}], {x, 0, m}], x] (* Amiram Eldar, May 14 2021 *)
PROG
(PARI) N=66; x='x+O('x^N); Vec(prod(k=1, N, ((1-x)^k-x^k)/((1-x)^k+x^k)))
CROSSREFS
Convolution inverse of A318570.
Sequence in context: A136663 A165490 A298819 * A265648 A181230 A262372
KEYWORD
sign
AUTHOR
Seiichi Manyama, Apr 12 2019
STATUS
approved