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 A356691 #14 Aug 23 2022 09:41:10
%S A356691 1,2,20,789,68692,10109085,2237436846,693885130771,287026057756824,
%T A356691 152677869816810537,101526778698168105370,82519543952519610272391,
%U A356691 80487081730821079456710228,92779662255769290691336848973,124775610962828705895908497741878
%N A356691 a(n) = n! * Sum_{k=0..n} k^(2*k)/k!.
%F A356691 a(0) = 1; a(n) = n*a(n-1) + n^(2*n).
%o A356691 (PARI) a(n) = n!*sum(k=0, n, k^(2*k)/k!);
%o A356691 (PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=i*v[i]+i^(2*i)); v;
%Y A356691 Cf. A062206, A277506, A350008, A356689.
%K A356691 nonn
%O A356691 0,2
%A A356691 _Seiichi Manyama_, Aug 23 2022