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 A383260 #13 Apr 21 2025 09:53:11
%S A383260 0,1,5,30,211,1691,15126,148975,1599401,18563832,231317677,3076301471,
%T A383260 43448641176,648950825173,10212710942609,168797691270438,
%U A383260 2921824286030527,52833169082034839,995732022426733782,19519908917429511307,397294691005861642805,8381466690394292755896
%N A383260 Expansion of e.g.f. f(x) * exp(f(x)), where f(x) = (exp(3*x) - 1)/3.
%F A383260 a(n) = Sum_{k=1..n} k * 3^(n-k) * Stirling2(n,k).
%o A383260 (PARI) a(n) = sum(k=1, n, k*3^(n-k)*stirling(n, k, 2));
%Y A383260 Cf. A138378, A383203.
%Y A383260 Cf. A024216, A383261, A383262.
%K A383260 nonn
%O A383260 0,3
%A A383260 _Seiichi Manyama_, Apr 21 2025