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 A367041 #15 Nov 03 2023 11:18:24 %S A367041 1,1,5,26,168,1195,8988,70318,566388,4665221,39113732,332691758, %T A367041 2863778072,24900264326,218372530380,1929363592870,17157018725000, %U A367041 153442147343648,1379250344938676,12453816724761706,112907775890596400,1027394297869071687 %N A367041 G.f. satisfies A(x) = 1 + x^2 + x*A(x)^4. %F A367041 a(n) = Sum_{k=0..floor(n/2)} binomial(3*(n-2*k)+1,k) * binomial(4*(n-2*k),n-2*k)/(3*(n-2*k)+1). %o A367041 (PARI) a(n) = sum(k=0, n\2, binomial(3*(n-2*k)+1, k)*binomial(4*(n-2*k), n-2*k)/(3*(n-2*k)+1)); %Y A367041 Cf. A176697, A367040. %Y A367041 Cf. A365178, A365180, A365181, A365182, A365183, A367048, A367049, A367050. %K A367041 nonn %O A367041 0,3 %A A367041 _Seiichi Manyama_, Nov 03 2023