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 A293839 #15 Oct 19 2017 06:13:21
%S A293839 1,1,2,8,38,238,1828,16096,160604,1826684,23018264,316422304,
%T A293839 4755059848,77084268712,1343682876272,25097562397952,498130253334032,
%U A293839 10479084018025744,233353674153699616,5470193826634531456,134766983204541259616,3482705318091355591136
%N A293839 E.g.f.: exp(Sum_{n>=1} A000009(n)*x^n/n).
%H A293839 Seiichi Manyama, <a href="/A293839/b293839.txt">Table of n, a(n) for n = 0..439</a>
%F A293839 a(0) = 1 and a(n) = (n-1)! * Sum_{k=1..n} A000009(k)*a(n-k)/(n-k)! for n > 0.
%t A293839 nmax = 20; CoefficientList[Series[E^Sum[PartitionsQ[k]*x^k/k, {k, 1, nmax}], {x, 0, nmax}], x] * Range[0, nmax]! (* _Vaclav Kotesovec_, Oct 18 2017 *)
%Y A293839 Cf. A293840, A293841.
%Y A293839 Cf. A215915.
%K A293839 nonn
%O A293839 0,3
%A A293839 _Seiichi Manyama_, Oct 17 2017