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 A371913 #7 Apr 12 2024 10:48:17 %S A371913 1,1,2,0,-6,12,67,-152,-740,2296,9017,-35979,-113936,579516,1454975, %T A371913 -9493390,-18317155,157178640,220172289,-2618995381,-2377680689, %U A371913 43783556265,19149194005,-732638868460,16196837316,12246524817736,-5891297294673 %N A371913 G.f. A(x) satisfies A(x) = 1 - x/A(x)^4 * (1 - A(x) - A(x)^5). %F A371913 a(n) = (1/n) * Sum_{k=0..n} binomial(n,k) * binomial(n-5*k,n-k-1) for n > 0. %o A371913 (PARI) a(n) = if(n==0, 1, sum(k=0, n, binomial(n, k)*binomial(n-5*k, n-k-1))/n); %Y A371913 Cf. A349332, A367725, A371914, A371915. %Y A371913 Cf. A371889, A371890. %K A371913 sign %O A371913 0,3 %A A371913 _Seiichi Manyama_, Apr 12 2024