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 A371269 #9 Mar 17 2024 05:40:56
%S A371269 1,0,2,3,76,485,10746,146167,3552312,75642345,2150551990,61400333291,
%T A371269 2061654862356,72804918721405,2858153637295698,119363732105632575,
%U A371269 5395737275060765296,259270058379207421649,13294348104095211012462,721446934706871966578899
%N A371269 E.g.f. satisfies A(x) = 1 + x*A(x) * (exp(x*A(x)^2) - 1).
%F A371269 a(n) = n! * Sum_{k=0..floor(n/2)} (2*n-k)! * Stirling2(n-k,k)/( (n-k)! * (2*n-2*k+1)! ).
%o A371269 (PARI) a(n) = n!*sum(k=0, n\2, (2*n-k)!*stirling(n-k, k, 2)/((n-k)!*(2*n-2*k+1)!));
%Y A371269 Cf. A371262, A371270, A371271.
%Y A371269 Cf. A371228.
%K A371269 nonn
%O A371269 0,3
%A A371269 _Seiichi Manyama_, Mar 16 2024