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 A377550 #8 Nov 01 2024 09:30:18
%S A377550 1,1,4,45,772,17865,525966,18794881,790175128,38221092657,
%T A377550 2091074167450,127675964340441,8606833626646740,634928943628432921,
%U A377550 50878715440232312374,4400937219238706030865,408700742920092110904496,40558224679468186878237153,4283310197644529184427059378
%N A377550 E.g.f. satisfies A(x) = 1 + x*A(x)*exp(x*A(x)^4).
%F A377550 a(n) = n! * Sum_{k=0..n} k^(n-k) * binomial(4*n-3*k+1,k)/( (4*n-3*k+1)*(n-k)! ).
%o A377550 (PARI) a(n) = n!*sum(k=0, n, k^(n-k)*binomial(4*n-3*k+1, k)/((4*n-3*k+1)*(n-k)!));
%Y A377550 Cf. A161633, A364980, A364981.
%Y A377550 Cf. A377551, A377552.
%K A377550 nonn
%O A377550 0,3
%A A377550 _Seiichi Manyama_, Oct 31 2024