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 A367831 #8 Dec 02 2023 13:14:11
%S A367831 1,2,17,529,60191,24822701,36413854321,186201636968159,
%T A367831 3260017071214457747,192544750449664642891369,
%U A367831 37901471231124512743264725077,24619109083914012570141331273785011,52334858943702505364559907161989713988743
%N A367831 E.g.f. A(x) satisfies A(x) = (1 + (exp(x) - 1) * A(3*x)) / (1 - x).
%F A367831 a(0) = 1; a(n) = n * a(n-1) + Sum_{k=1..n} 3^(n-k) * binomial(n,k) * a(n-k).
%o A367831 (PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=i*v[i]+sum(j=1, i, 3^(i-j)*binomial(i, j)*v[i-j+1])); v;
%Y A367831 Cf. A006155, A367830.
%Y A367831 Cf. A367836.
%K A367831 nonn
%O A367831 0,2
%A A367831 _Seiichi Manyama_, Dec 02 2023