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 A240560 #10 Jul 08 2019 11:33:27
%S A240560 0,0,1,0,-11,0,211,0,-6551,0,303271,0,-19665491,0,1704396331,0,
%T A240560 -190473830831,0,26684005437391,0,-4581126864886571,0,
%U A240560 946075012113714451,0,-231406946026650896711,0,66164529094650835995511,0,-21866924546405967976005251
%N A240560 a(n) = 2^n*E(n,1/2) + 2^(n+1)*E(n+1,0), where E(n,x) the Euler polynomials.
%F A240560 a(n) = skp(n, 0) + skp(n+1, -1), where skp(n, x) are the Swiss-Knife polynomials A153641.
%F A240560 a(n) = A122045(n) - A155585(n+1).
%p A240560 A240560 := n -> euler(n) + 2^(n+1)*euler(n+1, 0):
%p A240560 seq(A240560(n), n=0..28);
%t A240560 skp[n_, x_] := Sum[Binomial[n, k]*EulerE[k]*If[n==k, 1, x^(n-k)], {k, 0, n}];
%t A240560 a[n_] := skp[n, 0] + skp[n+1, -1];
%t A240560 Table[a[n], {n, 0, 28}] (* _Jean-François Alcover_, Jul 08 2019 *)
%Y A240560 Cf. A122045, A155585, A240559, A240561.
%K A240560 sign
%O A240560 0,5
%A A240560 _Peter Luschny_, Apr 17 2014