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 A381786 #7 Mar 07 2025 10:48:03
%S A381786 1,2,9,76,744,7986,90836,1075714,13122656,163769229,2080985186,
%T A381786 26832199993,350187469872,4617094718728,61406081813812,
%U A381786 822834184073768,11098254270705028,150555545320009712,2052839917410937693,28118478688846531072,386727880988105218913,5338557108832658927346
%N A381786 G.f. A(x) satisfies A(x) = (1 + x) * C(x*A(x)^3), where C(x) is the g.f. of A000108.
%F A381786 a(n) = Sum_{k=0..n} binomial(5*k+1,k) * binomial(3*k+1,n-k)/(5*k+1).
%o A381786 (PARI) a(n) = sum(k=0, n, binomial(5*k+1, k)*binomial(3*k+1, n-k)/(5*k+1));
%Y A381786 Cf. A234461, A381773, A381779, A381780.
%Y A381786 Cf. A000108.
%K A381786 nonn
%O A381786 0,2
%A A381786 _Seiichi Manyama_, Mar 07 2025