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 A321027 #17 Feb 16 2025 08:33:57
%S A321027 1,-2,6,-14,28,-58,114,-210,384,-684,1178,-2010,3372,-5538,9006,
%T A321027 -14466,22906,-35954,55884,-85946,131176,-198622,298274,-444958,
%U A321027 659368,-970544,1420362,-2066876,2990680,-4305598,6168154,-8793554,12480718,-17637250,24818530,-34785622
%N A321027 Expansion of Product_{k>0} theta_3(q^(2*k))/theta_3(q^(2*k-1)), where theta_3() is the Jacobi theta function.
%H A321027 Vaclav Kotesovec, <a href="/A321027/b321027.txt">Table of n, a(n) for n = 0..10000</a> (terms 0..1000 from Seiichi Manyama)
%H A321027 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/JacobiThetaFunctions.html">Jacobi Theta Functions</a>
%t A321027 nmax = 50; CoefficientList[Series[Product[EllipticTheta[3, 0, x^(2*k)] / EllipticTheta[3, 0, x^(2*k-1)], {k, 1, nmax}], {x, 0, nmax}], x] (* _Vaclav Kotesovec_, Oct 26 2018 *)
%Y A321027 Cf. A000122, A320067, A320098, A321026.
%K A321027 sign
%O A321027 0,2
%A A321027 _Seiichi Manyama_, Oct 26 2018