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 A364742 #12 Aug 05 2023 10:32:36
%S A364742 1,1,4,13,50,201,841,3627,15993,71803,327082,1508002,7023446,32995626,
%T A364742 156173668,744029238,3565030063,17169013899,83061503584,403483653745,
%U A364742 1967217524551,9623463731721,47220968518786,232354408276613,1146254897566224,5668118931395946
%N A364742 G.f. satisfies A(x) = 1 / (1 - x*(1 + x*A(x))^3).
%H A364742 Seiichi Manyama, <a href="/A364742/b364742.txt">Table of n, a(n) for n = 0..1000</a>
%F A364742 a(n) = (1/(n+1)) * Sum_{k=0..n} binomial(n+1,k) * binomial(3*k,n-k).
%o A364742 (PARI) a(n) = sum(k=0, n, binomial(n+1, k)*binomial(3*k, n-k))/(n+1);
%Y A364742 Cf. A001006, A161634, A364743, A364744.
%K A364742 nonn
%O A364742 0,3
%A A364742 _Seiichi Manyama_, Aug 05 2023