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 A383261 #9 Apr 21 2025 09:54:00
%S A383261 0,1,7,57,527,5441,61959,770281,10364671,149854545,2313932471,
%T A383261 37963374329,658873048623,12050610195937,231496456566631,
%U A383261 4657345160220681,97873704021590111,2143496712532350833,48821033290172899095,1154261436241093805593,28279753601438144211343
%N A383261 Expansion of e.g.f. f(x) * exp(2 * f(x)), where f(x) = (exp(3*x) - 1)/3.
%F A383261 a(n) = Sum_{k=1..n} k * 2^(k-1) * 3^(n-k) * Stirling2(n,k).
%o A383261 (PARI) a(n) = sum(k=1, n, k*2^(k-1)*3^(n-k)*stirling(n, k, 2));
%Y A383261 Cf. A024395, A383260.
%K A383261 nonn
%O A383261 0,3
%A A383261 _Seiichi Manyama_, Apr 21 2025