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 A377664 #7 Nov 14 2024 17:55:59
%S A377664 1,0,-3,46,497,-47524,-737891,218380506,4534099905,-3027853088648,
%T A377664 -79034002960099,99913537539058310,3145444161956190577,
%U A377664 -6725392006687056786732,-248035037340684934103427,829076907459643714597871026,35061737998144136797680434945,-172868475620109085260017037166096
%N A377664 a(n) = Sum_{j=0..n} binomial(n, j)*Euler(j, 0)*(2*n)^j. Main diagonal of A377666.
%p A377664 a := n -> local j; add(binomial(n, j)*euler(j, 0)*(2*n)^j, j = 0..n):
%p A377664 seq(a(n), n = 0..16);
%t A377664 a[0] := 1; a[n_] := Sum[Binomial[n, j] EulerE[j, 0] (2n)^j, {j, 0, n}];
%t A377664 Table[a[n], {n, 0, 16}]
%o A377664 (Python)
%o A377664 from math import comb
%o A377664 from sympy import euler
%o A377664 def A377664(n): return sum(comb(n,j)*euler(j,0)*(n<<1)**j for j in range(n+1)) # _Chai Wah Wu_, Nov 14 2024
%Y A377664 Cf. A377666.
%K A377664 sign
%O A377664 0,3
%A A377664 _Peter Luschny_, Nov 14 2024