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 A368524 #14 Dec 29 2023 08:07:04
%S A368524 0,1,6,30,180,1455,15666,213500,3521736,68101245,1508916310,
%T A368524 37661140506,1045012524348,31900040161899,1062139933257690,
%U A368524 38299757176168440,1486670929792295696,61800664096000744569,2738952078516469743678,128909373997071187219990
%N A368524 a(n) = Sum_{k=1..n} k^2 * n^(n-k).
%F A368524 a(n) = [x^n] x * (1+x)/((1-n*x) * (1-x)^3).
%F A368524 a(n) = n * (n+1) * (n^n - n^2 + n - 1)/(n-1)^3 for n > 1.
%o A368524 (PARI) a(n) = sum(k=1, n, k^2*n^(n-k));
%Y A368524 Cf. A062805, A368505, A368525.
%Y A368524 Cf. A368526, A368534.
%K A368524 nonn,easy
%O A368524 0,3
%A A368524 _Seiichi Manyama_, Dec 28 2023