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 A366700 #8 Oct 17 2023 08:34:26
%S A366700 1,5,26,258,3093,40333,558368,8051416,119614784,1818190754,
%T A366700 28142073936,442026009500,7027713442496,112879991541322,
%U A366700 1828959159551328,29857735697705720,490633308020085056,8108894353260093213,134705809490320133544
%N A366700 G.f. satisfies A(x) = (1 + x)^4 + x*A(x)^4.
%F A366700 a(n) = Sum_{k=0..n} binomial(4*(3*k+1),n-k) * binomial(4*k,k)/(3*k+1).
%o A366700 (PARI) a(n) = sum(k=0, n, binomial(4*(3*k+1), n-k)*binomial(4*k, k)/(3*k+1));
%Y A366700 Cf. A366267, A366698, A366699.
%K A366700 nonn
%O A366700 0,2
%A A366700 _Seiichi Manyama_, Oct 16 2023