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 A378063 #4 Nov 18 2024 13:01:12
%S A378063 1,1,-3,-26,1185,15376,-2749355,-49816976,22790134017,533858404096,
%T A378063 -498990299504499,-14365294449638912,23891962452055766497,
%U A378063 816609772823716089856,-2201371244223771530940315,-87139486416935710159898624,355987789164484245477279893505
%N A378063 a(n) = (-2*n)^n * Euler(n, (n - 1)/(2*n)) for n >= 1, and a(0) = 1. Main diagonal of A378066.
%F A378063 a(n) = Sum_{j=0..n} binomial(n, j)*Euler(j)*(-n)^j.
%p A378063 a := n -> ifelse(n = 0, 1, (-2*n)^n * euler(n, (n - 1)/(2*n))):
%p A378063 seq(a(n), n = 0..16);
%Y A378063 Cf. A378066.
%K A378063 sign
%O A378063 0,3
%A A378063 _Peter Luschny_, Nov 17 2024