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 A377889 #9 Nov 11 2024 06:47:01
%S A377889 1,2,21,472,16581,795736,48509641,3589729760,312603962985,
%T A377889 31321633489408,3549706188092541,448973808123051520,
%U A377889 62697159481460439469,9581292408000225087488,1590488540940006100524657,284993765391981838318575616,54826610288277007690469896017
%N A377889 E.g.f. A(x) satisfies A(x) = exp(x * A(x))/(1 - x*A(x)^3).
%F A377889 a(n) = n! * Sum_{k=0..n} (3*n-2*k+1)^(k-1) * binomial(4*n-3*k,n-k)/k!.
%o A377889 (PARI) a(n) = n!*sum(k=0, n, (3*n-2*k+1)^(k-1)*binomial(4*n-3*k, n-k)/k!);
%Y A377889 Cf. A352410, A377831, A377888.
%Y A377889 Cf. A373324.
%K A377889 nonn
%O A377889 0,2
%A A377889 _Seiichi Manyama_, Nov 10 2024