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 A372250 #12 Apr 25 2024 09:12:14
%S A372250 1,1,3,22,221,2796,44527,857074,19250457,494672824,14331709691,
%T A372250 462277166814,16430392693717,638087135544340,26885810437578471,
%U A372250 1221643263680551786,59548603124180235953,3099741728641090867056,171619335190080336331891
%N A372250 E.g.f. A(x) satisfies A(x) = exp( x * A(x) * (1 + x^2 * A(x)) ).
%H A372250 Seiichi Manyama, <a href="/A372250/b372250.txt">Table of n, a(n) for n = 0..376</a>
%F A372250 a(n) = n! * Sum_{k=0..floor(n/3)} (n-k+1)^(n-2*k-1) / (k! * (n-3*k)!).
%o A372250 (PARI) a(n) = n!*sum(k=0, n\3, (n-k+1)^(n-2*k-1)/(k!*(n-3*k)!));
%Y A372250 Cf. A088695, A138764.
%Y A372250 Cf. A362392.
%K A372250 nonn
%O A372250 0,3
%A A372250 _Seiichi Manyama_, Apr 24 2024