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 A303491 #14 Apr 28 2018 09:41:37
%S A303491 1,-2,0,-42,86,-1638,1428,-71286,218592,-3941590,5374096,-187901262,
%T A303491 661408902,-10769651242,18007942140,-597519823962,2262843922694,
%U A303491 -34034727280806,65527429637360,-1858398841872062,7543997928104274,-118580678725935186
%N A303491 Expansion of Product_{k>=1} ((1 - 8^k*x^k)/(1 + 8^k*x^k))^(1/8^k).
%H A303491 Seiichi Manyama, <a href="/A303491/b303491.txt">Table of n, a(n) for n = 0..1000</a>
%F A303491 G.f.: exp(Sum_{j>=1} ((1 - (-1)^j) / (j*(1 - 1/(8^(j-1)*x^j))) )). - _Vaclav Kotesovec_, Apr 25 2018
%t A303491 nmax = 30; CoefficientList[Series[Exp[Sum[(1 - (-1)^j) / (j*(1 - 1/(8^(j-1)*x^j))), {j, 1, nmax}]], {x, 0, nmax}], x] (* _Vaclav Kotesovec_, Apr 25 2018 *)
%o A303491 (PARI) N=66; x='x+O('x^N); Vec(prod(k=1, N, ((1-8^k*x^k)/(1+8^k*x^k))^(1/8^k)))
%Y A303491 Cf. A303395, A303439, A303443, A303490.
%K A303491 sign
%O A303491 0,2
%A A303491 _Seiichi Manyama_, Apr 24 2018