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 A261635 #4 Aug 28 2015 03:15:45
%S A261635 1,4,10,20,39,72,124,204,331,524,806,1216,1813,2660,3846,5500,7790,
%T A261635 10916,15158,20880,28544,38736,52226,69972,93200,123460,162700,213340,
%U A261635 278459,361860,468252,603484,774844,991220,1263576,1605392,2033172,2566972,3231338
%N A261635 Expansion of Product_{k>=0} 1/(1-x^(3*k+1))^4.
%F A261635 a(n) ~ exp(2*Pi*sqrt(2*n)/3) * Gamma(1/3)^4 / (8 * 2^(1/12) * sqrt(3) * Pi^(8/3) * n^(5/12)).
%t A261635 nmax=50; CoefficientList[Series[Product[1/(1-x^(3*k+1))^4, {k, 0, nmax}], {x, 0, nmax}], x]
%Y A261635 Cf. A035382, A261616, A261636.
%K A261635 nonn
%O A261635 0,2
%A A261635 _Vaclav Kotesovec_, Aug 27 2015