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 A379192 #6 Dec 18 2024 09:28:08
%S A379192 1,4,27,235,2344,25374,289906,3441015,42017262,524418639,6660297019,
%T A379192 85796763321,1118314903447,14722203914653,195465862293738,
%U A379192 2614323606027841,35191188308646852,476390139438508209,6481416282265645008,88577523301166187997,1215421503348039618483
%N A379192 G.f. A(x) satisfies A(x) = (1 + x*A(x))^3/(1 - x*A(x)^2).
%F A379192 a(n) = Sum_{k=0..n} binomial(n+2*k+1,k) * binomial(3*n+3*k+3,n-k)/(n+2*k+1).
%o A379192 (PARI) a(n) = sum(k=0, n, binomial(n+2*k+1, k)*binomial(3*n+3*k+3, n-k)/(n+2*k+1));
%Y A379192 Cf. A307678, A379191.
%K A379192 nonn
%O A379192 0,2
%A A379192 _Seiichi Manyama_, Dec 17 2024