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 A367924 #13 Dec 05 2023 09:01:38
%S A367924 1,3,20,200,2666,44422,888214,20719722,552385386,16567346630,
%T A367924 552104425070,20238679934002,809341290336274,35062535546332062,
%U A367924 1635835480858764342,81770970437144725034,4360009179878123161658,247004345719314584973430
%N A367924 Expansion of e.g.f. 1/(3 - x - 2*exp(x)).
%F A367924 a(0) = 1; a(n) = n * a(n-1) + 2 * Sum_{k=1..n} binomial(n,k) * a(n-k).
%o A367924 (PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=i*v[i]+2*sum(j=1, i, binomial(i, j)*v[i-j+1])); v;
%Y A367924 Cf. A006155, A367925.
%Y A367924 Cf. A004123, A367830, A367835, A367922.
%K A367924 nonn
%O A367924 0,2
%A A367924 _Seiichi Manyama_, Dec 05 2023