OFFSET
0,3
FORMULA
a(n) ~ (-1)^n * cos(Pi/(2*sqrt(2))) * 2^(5*n+3) * n^(2*n + 1/2) / (Pi^(2*n + 1/2) * exp(2*n)). - Vaclav Kotesovec, Apr 03 2024
MAPLE
seq(add(2^(3*k)*binomial(2*n, 2*k)*euler(2*k, 1/2), k = 0..n), n = 0..15);
MATHEMATICA
Table[Sum[2^(3*k)*Binomial[2*n, 2*k]*EulerE[2*k, 1/2], {k, 0, n}], {n, 0, 20}] (* Paolo Xausa, Apr 17 2024 *)
CROSSREFS
KEYWORD
sign
AUTHOR
Peter Luschny, Apr 03 2024
STATUS
approved