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 A366677 #13 Oct 16 2023 09:27:53
%S A366677 1,1,4,22,141,973,7112,54040,422552,3377770,27478568,226753828,
%T A366677 1893462584,15969598554,135842638632,1164075017512,10039732285528,
%U A366677 87081507756245,759128176746864,6647475055207618,58445784269830824,515745587816906733
%N A366677 G.f. satisfies A(x) = 1 + x^4 + x*A(x)^4.
%F A366677 a(n) = Sum_{k=0..floor(n/4)} binomial(3*(n-4*k)+1,k) * binomial(4*(n-4*k),n-4*k)/(3*(n-4*k)+1).
%o A366677 (PARI) a(n) = sum(k=0, n\4, binomial(3*(n-4*k)+1, k)*binomial(4*(n-4*k), n-4*k)/(3*(n-4*k)+1));
%Y A366677 Cf. A176697, A366676.
%Y A366677 Cf. A366267, A366558.
%K A366677 nonn
%O A366677 0,3
%A A366677 _Seiichi Manyama_, Oct 16 2023