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 A355422 #16 Jul 02 2022 10:07:30
%S A355422 1,10,130,2000,35054,684000,14628190,338990000,8438270014,
%T A355422 224070580800,6311530677150,187702155610000,5870416574854974,
%U A355422 192423935736656800,6591135679171866910,235315671951948070000,8736534653549465359934
%N A355422 Expansion of e.g.f. exp(Sum_{k=1..4} (exp(k*x) - 1)).
%F A355422 a(0) = 1; a(n) = Sum_{k=1..n} (1 + 2^k + 3^k + 4^k) * binomial(n-1,k-1) * a(n-k).
%o A355422 (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(exp(sum(k=1, 4, exp(k*x)-1))))
%o A355422 (PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=1, i, (1+2^j+3^j+4^j)*binomial(i-1, j-1)*v[i-j+1])); v;
%Y A355422 Column k=4 of A355423.
%Y A355422 Cf. A004702, A306028.
%K A355422 nonn
%O A355422 0,2
%A A355422 _Seiichi Manyama_, Jul 01 2022