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 A110140 #8 Sep 16 2021 04:51:13
%S A110140 1,1,2,4,11,31,103,351,1321,5113,21201,90465,406621,1879021,9051309,
%T A110140 44754061,229059633,1201271409,6488957521,35853950609,203303964341,
%U A110140 1177299817093,6976709899853,42161309544541,260154190137865
%N A110140 Binomial transform of n^n (with interpolated zeros).
%C A110140 Binomial transform of 1,0,1,0,4,0,27,....
%F A110140 a(n)=sum{k=0..n, C(n, k)(k/2)^(k/2)*(1+(-1)^k)/2}
%t A110140 Table[1 + Sum[Binomial[n, k]*(k/2)^(k/2)*(1 + (-1)^k)/2, {k, 1, n}], {n, 0, 30}] (* _Vaclav Kotesovec_, Oct 30 2017 *)
%Y A110140 Cf. A000312, A086331, A294353.
%K A110140 easy,nonn
%O A110140 0,3
%A A110140 _Paul Barry_, Jul 13 2005