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 A265820 #6 Dec 15 2015 18:59:17
%S A265820 1,0,2,0,4,5,8,10,24,20,73,51,146,142,306,409,731,835,1662,1828,3969,
%T A265820 4251,8256,9525,17814,22565,38629,47424,82916,101387,185271,218421,
%U A265820 386140,468783,806005,1040428,1696283,2160026,3567221,4498026,7683250,9446666
%N A265820 Expansion of Product_{k>=1} 1/(1 - (3*k-1)*x^(3*k-1)).
%H A265820 Vaclav Kotesovec, <a href="/A265820/b265820.txt">Table of n, a(n) for n = 0..5000</a>
%F A265820 a(n) ~ c * 2^(n/2), where
%F A265820 c = 14.317325023208603416271945494838289608390197678435231... if n is even,
%F A265820 c = 13.388403642510880418401945468592189683402616378443965... if n is odd.
%t A265820 nmax = 40; CoefficientList[Series[Product[1/(1 - (3*k-1)*x^(3*k-1)), {k, 1, nmax}], {x, 0, nmax}], x]
%Y A265820 Cf. A067553, A265821.
%K A265820 nonn
%O A265820 0,3
%A A265820 _Vaclav Kotesovec_, Dec 15 2015