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 A347665 #5 Sep 10 2021 19:22:47
%S A347665 1,2,8,39,227,1518,11368,93796,842416,8158942,84581560,932878169,
%T A347665 10891741957,134043979644,1732583270218,23445954950207,
%U A347665 331260511278659,4874617929283392,74548457001207068,1182551615010825076,19423368875596930596,329809489306236629874
%N A347665 E.g.f.: exp( exp(x) * (1 + x + x^2 / 2) - 1 ).
%C A347665 Exponential transform of A000124.
%F A347665 a(0) = 1; a(n) = Sum_{k=1..n} binomial(n-1,k-1) * A000124(k) * a(n-k).
%t A347665 nmax = 21; CoefficientList[Series[Exp[Exp[x] (1 + x + x^2/2) - 1], {x, 0, nmax}], x] Range[0, nmax]!
%t A347665 a[0] = 1; a[n_] := a[n] = Sum[Binomial[n - 1, k - 1] (k (k + 1)/2 + 1) a[n - k], {k, 1, n}]; Table[a[n], {n, 0, 21}]
%Y A347665 Cf. A000085, A000124, A209801, A279361, A347666.
%K A347665 nonn
%O A347665 0,2
%A A347665 _Ilya Gutkovskiy_, Sep 10 2021