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 A265974 #11 Aug 23 2019 20:50:13
%S A265974 1,3,15,54,210,699,2484,7995,26610,84186,269940,839238,2634579,
%T A265974 8098194,25032282,76388265,233791104,709501596,2157488730,6523204836,
%U A265974 19747491810,59558682132,179762506329,541222906812,1630300772106,4902697929306,14748249476553
%N A265974 Expansion of Product_{k>=1} 1/(1 - 3*k*x^k).
%H A265974 Vaclav Kotesovec, <a href="/A265974/b265974.txt">Table of n, a(n) for n = 0..1000</a>
%F A265974 a(n) ~ c * 3^n, where c = Product_{m>=2} 1/(1 - m/3^(m-1)) = 5.86277744540963226378877460838259757442241952947887939654316926419876...
%p A265974 b:= proc(n, i) option remember; `if`(n=0 or i=1,
%p A265974 3^n, b(n, i-1) +i*3*b(n-i, min(n-i, i)))
%p A265974 end:
%p A265974 a:= n-> b(n$2):
%p A265974 seq(a(n), n=0..32); # _Alois P. Heinz_, Aug 23 2019
%t A265974 nmax=40; CoefficientList[Series[Product[1/(1-3*k*x^k), {k, 1, nmax}], {x, 0, nmax}], x]
%Y A265974 Cf. A006906, A265951, A265975, A265976.
%Y A265974 Cf. A246935, A242587.
%K A265974 nonn
%O A265974 0,2
%A A265974 _Vaclav Kotesovec_, Dec 19 2015