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 A377705 #26 Dec 13 2024 09:40:31
%S A377705 1,1,0,2,-3,12,-35,121,-413,1464,-5265,19249,-71236,266443,-1005511,
%T A377705 3824055,-14641264,56389272,-218315173,849170605,-3316817080,
%U A377705 13004273475,-51160638706,201901154910,-799059730844,3170706566751,-12611882813645,50277271079611
%N A377705 G.f. A(x) satisfies A(x) = 1 + x/A(x)^2 * (1 - A(x) + A(x)^3).
%F A377705 a(n) = (1/n) * Sum_{k=0..n} (-1)^k * binomial(n,k) * binomial(n-3*k,n-k-1) for n > 0.
%o A377705 (PARI) a(n) = if(n==0, 1, sum(k=0, n, (-1)^k*binomial(n, k)*binomial(n-3*k, n-k-1))/n);
%Y A377705 Cf. A115344, A127897, A364758, A365225, A378892.
%Y A377705 Cf. A371889.
%K A377705 sign
%O A377705 0,4
%A A377705 _Seiichi Manyama_, Dec 12 2024