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 A261651 #4 Aug 28 2015 05:07:28
%S A261651 1,6,18,38,72,138,254,432,708,1154,1836,2826,4288,6456,9552,13902,
%T A261651 20070,28722,40614,56916,79242,109448,149988,204318,276672,372288,
%U A261651 498264,663602,879252,1159470,1522564,1990788,2592162,3362638,4346244,5597100,7183792,9191004
%N A261651 Expansion of Product_{k>=0} ((1+x^(3*k+1))/(1-x^(3*k+1)))^3.
%F A261651 a(n) ~ exp(Pi*sqrt(n)) * Gamma(1/3)^3 / (4 * Pi^2 * sqrt(3*n)).
%t A261651 nmax=60; CoefficientList[Series[Product[((1+x^(3*k+1))/(1-x^(3*k+1)))^3,{k,0,nmax}],{x,0,nmax}],x]
%Y A261651 Cf. A015128, A156616, A080054, A007096, A261610, A261649.
%K A261651 nonn
%O A261651 0,2
%A A261651 _Vaclav Kotesovec_, Aug 28 2015