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 A308037 #14 Jun 30 2025 20:58:54
%S A308037 1,2,2,9,2,123,2,1830,3027,43038,2,2023728,2,49337473,213142023,
%T A308037 2313595723,2,216927216877,2,6712023695345,82312699558575,
%U A308037 366282502967439,2,113350450913387211,2436684974110753,1850568574287104493,106563274551407600878,231678790379913209098,2
%N A308037 a(n) = Sum_{d|n} Stirling2(n,d).
%H A308037 Alois P. Heinz, <a href="/A308037/b308037.txt">Table of n, a(n) for n = 1..579</a>
%F A308037 a(n) = 2 <=> n is prime <=> n in { A000040 }. - _Alois P. Heinz_, May 10 2019
%p A308037 a:= n-> add(Stirling2(n, d), d=numtheory[divisors](n)):
%p A308037 seq(a(n), n=1..30); # _Alois P. Heinz_, May 10 2019
%t A308037 a[n_] := a[n] = Sum[StirlingS2[n, d], {d, Divisors[n]}]; Table[a[n], {n, 1, 29}]
%o A308037 (PARI) a(n) = sumdiv(n, d, stirling(n, d, 2)); \\ _Michel Marcus_, May 10 2019
%Y A308037 Cf. A000040, A008277, A056045, A096308.
%K A308037 nonn
%O A308037 1,2
%A A308037 _Ilya Gutkovskiy_, May 10 2019