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 A303343 #13 Apr 14 2019 11:55:20
%S A303343 1,-2,-2,-12,-90,-968,-12764,-200464,-3674378,-76958942,-1814783184,
%T A303343 -47618072204,-1376556963244,-43481881639608,-1490306874257184,
%U A303343 -55091497907730000,-2185104061817592618,-92567886910879671396,-4171638481112174023226
%N A303343 Expansion of Product_{n>=1} ((1 - (n*x)^n)/(1 + (n*x)^n))^(1/n).
%F A303343 a(n) ~ -2 * n^(n-1). - _Vaclav Kotesovec_, Apr 25 2018
%F A303343 G.f.: exp(Sum_{k>=1} (sigma_k(k) - sigma_k(2*k))*x^k/(2^(k-1)*k)). - _Ilya Gutkovskiy_, Apr 14 2019
%o A303343 (PARI) N=66; x='x+O('x^N); Vec(prod(k=1, N, ((1-(k*x)^k)/(1+(k*x)^k))^(1/k)))
%Y A303343 Cf. A303306, A303344.
%K A303343 sign
%O A303343 0,2
%A A303343 _Seiichi Manyama_, Apr 22 2018