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 A365285 #10 Aug 31 2023 08:16:43 %S A365285 1,1,2,6,48,480,5040,57960,806400,13426560,250992000,5102697600, %T A365285 113283878400,2760905347200,73287883468800,2093750122464000, %U A365285 63947194517606400,2082970788291993600,72182922107859763200,2651026034089585152000 %N A365285 E.g.f. satisfies A(x) = 1 + x*A(x)*exp(x^3*A(x)). %F A365285 a(n) = n! * Sum_{k=0..floor(n/3)} (n-3*k)^k * binomial(n-2*k+1,n-3*k)/( (n-2*k+1)*k! ). %o A365285 (PARI) a(n) = n!*sum(k=0, n\3, (n-3*k)^k*binomial(n-2*k+1, n-3*k)/((n-2*k+1)*k!)); %Y A365285 Cf. A358065, A365286, A365287. %Y A365285 Cf. A365282. %K A365285 nonn %O A365285 0,3 %A A365285 _Seiichi Manyama_, Aug 31 2023