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 A252710 #5 Dec 20 2014 16:24:08
%S A252710 2,19,270,5274,131250,3971953,141615782,5814096100,270145723914,
%T A252710 14014491434175,802959561033630,50357860270776302,3431283333644097698,
%U A252710 252413829036827831821,19937800344936448113750,1683065517269356710047112,151213514611062314791034874
%N A252710 Sum_{k=0..n} k^(n-k)*(n+k)^k.
%F A252710 a(n) ~ 2^n * n^n / (1-exp(-1/2)/2). - _Vaclav Kotesovec_, Dec 20 2014
%t A252710 Table[Sum[k^(n-k)*(n+k)^k, {k, 0, n}], {n, 1, 20}]
%Y A252710 Cf. A062817, A252708, A252709.
%K A252710 nonn,easy
%O A252710 1,1
%A A252710 _Vaclav Kotesovec_, Dec 20 2014