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 A368466 #12 Dec 26 2023 05:09:21
%S A368466 1,2,18,250,4810,118458,3557610,126109562,5153959338,238596116794,
%T A368466 12340467941098,705262375055610,44135963944338474,3001795007526424250,
%U A368466 220466095716711140202,17389850740043552754298,1466156761178169939270826,131580021359494993268692026
%N A368466 a(n) = Sum_{k=0..n} 2^k * k^n.
%F A368466 a(n) ~ 2^n * n^n / (1 - exp(-1)/2). - _Vaclav Kotesovec_, Dec 26 2023
%o A368466 (PARI) a(n) = sum(k=0, n, 2^k*k^n);
%Y A368466 Main diagonal of A368479.
%Y A368466 Cf. A031971, A120485, A349963.
%K A368466 nonn,easy
%O A368466 0,2
%A A368466 _Seiichi Manyama_, Dec 25 2023