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 A371889 #6 Apr 11 2024 10:10:27
%S A371889 1,1,2,2,-1,-4,7,33,-5,-200,-151,1185,2202,-6069,-21799,21791,182718,
%T A371889 26520,-1349611,-1613331,8674338,21651795,-44750412,-217666394,
%U A371889 121538304,1859974399,1023915107,-13828122997,-23155237537,86925632115,282182920662
%N A371889 G.f. A(x) satisfies A(x) = 1 - x/A(x)^2 * (1 - A(x) - A(x)^3).
%F A371889 a(n) = (1/n) * Sum_{k=0..n} binomial(n,k) * binomial(n-3*k,n-k-1) for n > 0.
%o A371889 (PARI) a(n) = if(n==0, 1, sum(k=0, n, binomial(n, k)*binomial(n-3*k, n-k-1))/n);
%Y A371889 Cf. A243156, A307678, A364747, A365192.
%K A371889 sign
%O A371889 0,3
%A A371889 _Seiichi Manyama_, Apr 11 2024