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 A261649 #4 Aug 28 2015 05:06:57
%S A261649 1,4,8,12,20,36,56,80,120,180,252,348,492,680,912,1228,1652,2180,2856,
%T A261649 3744,4860,6256,8044,10284,13048,16520,20848,26140,32672,40756,50596,
%U A261649 62576,77256,95060,116540,142592,174036,211736,257056,311448,376332,453764,546160
%N A261649 Expansion of Product_{k>=0} ((1+x^(3*k+1))/(1-x^(3*k+1)))^2.
%F A261649 a(n) ~ exp(Pi*sqrt(2*n/3)) * Gamma(1/3)^2 / (2^(7/4) * 3^(5/12) * Pi^(4/3) * n^(7/12)).
%t A261649 nmax=60; CoefficientList[Series[Product[((1+x^(3*k+1))/(1-x^(3*k+1)))^2,{k,0,nmax}],{x,0,nmax}],x]
%Y A261649 Cf. A015128, A156616, A080054, A007096, A261610, A261651.
%K A261649 nonn
%O A261649 0,2
%A A261649 _Vaclav Kotesovec_, Aug 28 2015