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 A364596 #11 Jul 29 2023 10:55:13 %S A364596 1,1,1,2,4,7,15,36,82,191,471,1166,2884,7267,18523,47349,121821, %T A364596 315781,822165,2148811,5641035,14864295,39287907,104154066,276899112, %U A364596 737984583,1971375679,5277570860,14156881590,38045460023,102421374775,276174537027,745822179831 %N A364596 G.f. satisfies A(x) = 1/(1-x) + x^3*(1-x)*A(x)^4. %F A364596 a(n) = Sum_{k=0..floor(n/3)} binomial(n-k,2*k) * binomial(4*k,k) / (3*k+1). %o A364596 (PARI) a(n) = sum(k=0, n\3, binomial(n-k, 2*k)*binomial(4*k, k)/(3*k+1)); %Y A364596 Cf. A364595, A364597. %Y A364596 Cf. A215340, A226974. %Y A364596 Cf. A364592, A364594. %K A364596 nonn,easy %O A364596 0,4 %A A364596 _Seiichi Manyama_, Jul 29 2023