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 A381914 #13 Mar 10 2025 09:42:53
%S A381914 1,2,10,72,624,6009,61809,664813,7384613,84045565,974913510,
%T A381914 11483316680,136974177209,1651166320547,20083352214058,
%U A381914 246168280262403,3037682020219285,37706043912831337,470482875049515074,5897864081341146065,74243055437832292562,938101296155866961124
%N A381914 Expansion of (1/x) * Series_Reversion( x * (1-x) / B(x) ), where B(x) is the g.f. of A002293.
%F A381914 G.f. A(x) satisfies A(x) = B(x*A(x)) / (1 - x*A(x)).
%F A381914 a(n) = Sum_{k=0..n} binomial(n+4*k+1,k) * binomial(2*n-k,n-k)/(n+4*k+1).
%o A381914 (PARI) a(n) = sum(k=0, n, binomial(n+4*k+1, k)*binomial(2*n-k, n-k)/(n+4*k+1));
%Y A381914 Cf. A381915, A381916.
%Y A381914 Cf. A381817, A381911.
%Y A381914 Cf. A002293.
%K A381914 nonn
%O A381914 0,2
%A A381914 _Seiichi Manyama_, Mar 10 2025