a(n) = (4*n)! * [z^(4*n)] exp(1 - (cos(z) + cosh(z))/2).

A291976

a(n) = (4*n)! * [z^(4*n)] exp(1 - (cos(z) + cosh(z))/2).

Terms

    a(0) =1a(1) =-1a(2) =34a(3) =-5281a(4) =2185429a(5) =-1854147586

External references