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 A367875 #16 Feb 03 2024 10:15:28
%S A367875 1,4,18,91,512,3169,21352,155257,1209680,10039825,88318136,819958033,
%T A367875 8004898600,81913041721,876117919616,9770201709649,113347591376672,
%U A367875 1365288066794017,17043527322085096,220145837754233713,2937871757773069496,40451715334029650953
%N A367875 Expansion of e.g.f. exp(x * (3 + exp(x))).
%F A367875 G.f.: Sum_{k>=0} x^k / (1 - (k+3)*x)^(k+1).
%F A367875 a(n) = Sum_{k=0..n} (k+3)^(n-k) * binomial(n,k).
%F A367875 a(0) = 1; a(n) = 3 * a(n-1) + Sum_{k=1..n} binomial(n-1,k-1) * k * a(n-k). - _Ilya Gutkovskiy_, Feb 02 2024
%o A367875 (PARI) a(n) = sum(k=0, n, (k+3)^(n-k)*binomial(n, k));
%Y A367875 Cf. A000248, A080108, A367874.
%Y A367875 Cf. A245834.
%K A367875 nonn,easy
%O A367875 0,2
%A A367875 _Seiichi Manyama_, Dec 03 2023