This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A004404 #32 Oct 26 2023 00:19:51
%S A004404 1,-6,24,-80,234,-624,1552,-3648,8184,-17654,36816,-74544,147056,
%T A004404 -283440,535008,-990912,1803882,-3232224,5707624,-9943536,17106960,
%U A004404 -29088352,48922320,-81438528,134261584,-219336630,355242288
%N A004404 Expansion of 1 / (Sum_{n=-oo..oo} x^(n^2))^3.
%H A004404 Seiichi Manyama, <a href="/A004404/b004404.txt">Table of n, a(n) for n = 0..10000</a> (terms 0..4000 from Robert Israel)
%H A004404 Vaclav Kotesovec, <a href="http://arxiv.org/abs/1509.08708">A method of finding the asymptotics of q-series based on the convolution of generating functions</a>, arXiv:1509.08708 [math.CO], Sep 30 2015, p. 8.
%F A004404 a(n) ~ (-1)^n * 3*exp(Pi*sqrt(3*n)) / (64*n^(3/2)) * (1 - sqrt(3)/(Pi*sqrt(n))). - _Vaclav Kotesovec_, Aug 18 2015, extended Jan 16 2017
%p A004404 S:= series(1/JacobiTheta3(0,x)^3,x,101):
%p A004404 seq(coeff(S,x,j),j=0..100); # _Robert Israel_, Dec 29 2015
%t A004404 nmax = 30; CoefficientList[Series[Product[((1 + (-x)^k)/(1 - (-x)^k))^3, {k, 1, nmax}], {x, 0, nmax}], x] (* _Vaclav Kotesovec_, Aug 18 2015 *)
%Y A004404 Cf. A001934, A004405-A004425, A015128.
%K A004404 sign
%O A004404 0,2
%A A004404 _N. J. A. Sloane_