login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A320070
Expansion of 1/(theta_3(q) * theta_3(q^2) * theta_3(q^3)), where theta_3() is the Jacobi theta function.
2
1, -2, 2, -6, 14, -20, 32, -60, 98, -150, 232, -360, 558, -828, 1196, -1776, 2614, -3700, 5238, -7480, 10516, -14592, 20180, -27832, 38216, -51970, 70184, -94842, 127612, -170140, 226164, -300324, 396754, -521520, 683484, -893432, 1164330, -1511188, 1954756, -2524188
OFFSET
0,2
LINKS
FORMULA
Convolution inverse of A029594.
a(n) ~ (-1)^n * exp(2*Pi*sqrt(n/3)) / (4*sqrt(6)*n^(3/2)). - Vaclav Kotesovec, Oct 05 2018
MATHEMATICA
CoefficientList[Series[1/Product[EllipticTheta[3, 0, q^k], {k, 1, 3}], {q, 0, 80}], q] (* G. C. Greubel, Oct 29 2018 *)
PROG
(PARI) q='q+O('q^80); Vec(1/prod(k=1, 3, eta(q^(2*k))^5/(eta(q^k)* eta(q^(4*k)))^2 )) \\ G. C. Greubel, Oct 29 2018
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Oct 05 2018
STATUS
approved