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 A303344 #15 Apr 14 2019 11:55:26
%S A303344 1,2,6,28,182,1640,19220,278224,4809942,96598622,2208156512,
%T A303344 56580566908,1605518324884,49963000166616,1691615823420800,
%U A303344 61897541544248720,2433873670903995990,102341746590575878628,4582360425862350559350,217661837260679635780356
%N A303344 Expansion of Product_{n>=1} ((1 + (n*x)^n)/(1 - (n*x)^n))^(1/n).
%F A303344 a(n) ~ 2 * n^(n-1). - _Vaclav Kotesovec_, Apr 22 2018
%F A303344 G.f.: exp(Sum_{k>=1} (sigma_k(2*k) - sigma_k(k))*x^k/(2^(k-1)*k)). - _Ilya Gutkovskiy_, Apr 14 2019
%t A303344 nmax = 20; CoefficientList[Series[Product[((1 + (k*x)^k)/(1 - (k*x)^k))^(1/k), {k, 1, nmax}], {x, 0, nmax}], x] (* _Vaclav Kotesovec_, Apr 22 2018 *)
%o A303344 (PARI) N=66; x='x+O('x^N); Vec(prod(k=1, N, ((1+(k*x)^k)/(1-(k*x)^k))^(1/k)))
%Y A303344 Cf. A023881, A186633, A303307, A303343.
%K A303344 nonn
%O A303344 0,2
%A A303344 _Seiichi Manyama_, Apr 22 2018