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 A355101 #10 Jun 19 2022 08:40:41
%S A355101 1,3,18,189,2952,63225,1759374,61261200,2595618720,130963993263,
%T A355101 7734817065600,527276606418837,41005535326851456,3602215645092352314,
%U A355101 354438336568129922052,38776184401330464272910,4686507224871009709115232,622194587177907979874119473
%N A355101 E.g.f. A(x) satisfies A(x) = 1 + 3 * x * A(exp(x) - 1).
%F A355101 a(0) = 1; a(n) = 3 * n * Sum_{k=0..n-1} Stirling2(n-1,k) * a(k).
%F A355101 a(n) = 3 * n * A355092(n-1) for n>0.
%o A355101 (PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=3*i*sum(j=0, i-1, stirling(i-1, j, 2)*v[j+1])); v;
%Y A355101 Cf. A048801, A355100.
%Y A355101 Cf. A355092.
%K A355101 nonn
%O A355101 0,2
%A A355101 _Seiichi Manyama_, Jun 19 2022