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 A372347 #5 Jun 23 2024 16:12:39
%S A372347 1,1,2,4,12,52,334,2866,31902,439510,7372150,147351714,3460114654,
%T A372347 94073798158,2926942982790,103161703653178,4084845678671086,
%U A372347 180433041383154870,8836346732709839206,477142911818397135058,28265453383985064929934
%N A372347 a(n) = Sum_{j=0..n} p(n - j, j) where p(n, x) = Sum_{k=0..n} k! * Stirling1(n, k) * x^k.
%p A372347 p := n -> local k; add(k!*Stirling1(n, k)*x^k, k = 0..n):
%p A372347 a := n -> local j; add(subs(x=j, p(n - j)), j = 0..n):
%p A372347 seq(a(n), n = 0..21);
%Y A372347 Cf. A225479.
%K A372347 nonn
%O A372347 0,3
%A A372347 _Peter Luschny_, Apr 28 2024