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 A355787 #10 Jul 17 2022 11:01:38
%S A355787 1,1,1,6,17,220,939,20930,107393,3823416,20382195,1147905462,
%T A355787 5519388225,515034742404,1817577994491,323878306632330,
%U A355787 481078381979649,272556878473903344,-355395800536648605,296393140746445749246,-1420979986049970526335
%N A355787 E.g.f. satisfies A(x) = (1 + 2*x)^(A(x)/2).
%F A355787 E.g.f.: exp( -LambertW(-log(1+2*x)/2) ).
%F A355787 a(n) = Sum_{k=0..n} 2^(n-k) * (k+1)^(k-1) * Stirling1(n,k).
%o A355787 (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(-lambertw(-log(1+2*x)/2))))
%o A355787 (PARI) a(n) = sum(k=0, n, 2^(n-k)*(k+1)^(k-1)*stirling(n, k, 1));
%Y A355787 Cf. A033917, A355780.
%K A355787 sign
%O A355787 0,4
%A A355787 _Seiichi Manyama_, Jul 17 2022