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 A371271 #9 Mar 17 2024 04:06:59
%S A371271 1,0,2,3,124,725,28146,352807,14395256,298559529,13269150190,
%T A371271 394087597211,19361289265044,752705527798237,41083484117561354,
%U A371271 1970818974867113295,119467697774656366576,6792102349650727753553,455778318504089893121766
%N A371271 E.g.f. satisfies A(x) = 1 + x*A(x)^3 * (exp(x*A(x)^2) - 1).
%F A371271 a(n) = (n!/(2*n+1)!) * Sum_{k=0..floor(n/2)} (2*n+k)! * Stirling2(n-k,k)/(n-k)!.
%o A371271 (PARI) a(n) = n!*sum(k=0, n\2, (2*n+k)!*stirling(n-k, k, 2)/(n-k)!)/(2*n+1)!;
%Y A371271 Cf. A371262, A371269, A371270.
%Y A371271 Cf. A371230.
%K A371271 nonn
%O A371271 0,3
%A A371271 _Seiichi Manyama_, Mar 16 2024