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 A303490 #15 Apr 28 2018 09:41:18
%S A303490 1,-2,0,-10,22,-102,84,-950,3360,-18006,21968,-162126,613830,-2772010,
%T A303490 3847740,-38669210,145735622,-567469350,901506480,-6688787966,
%U A303490 27166965906,-137118406226,234942672620,-1425038557410,6527750118052,-27227710098826
%N A303490 Expansion of Product_{k>=1} ((1 - 4^k*x^k)/(1 + 4^k*x^k))^(1/4^k).
%H A303490 Seiichi Manyama, <a href="/A303490/b303490.txt">Table of n, a(n) for n = 0..1000</a>
%F A303490 G.f.: exp(Sum_{j>=1} ((1 - (-1)^j) / (j*(1 - 1/(4^(j-1)*x^j))) )). - _Vaclav Kotesovec_, Apr 25 2018
%t A303490 nmax = 30; CoefficientList[Series[Exp[Sum[(1 - (-1)^j) / (j*(1 - 1/(4^(j-1)*x^j))), {j, 1, nmax}]], {x, 0, nmax}], x] (* _Vaclav Kotesovec_, Apr 25 2018 *)
%o A303490 (PARI) N=66; x='x+O('x^N); Vec(prod(k=1, N, ((1-4^k*x^k)/(1+4^k*x^k))^(1/4^k)))
%Y A303490 Cf. A303394, A303439, A303442, A303491.
%K A303490 sign
%O A303490 0,2
%A A303490 _Seiichi Manyama_, Apr 24 2018