a(n) = w(n+1)/(4*w(n)), where w = A203424.

A203425

a(n) = w(n+1)/(4*w(n)), where w = A203424.

Terms

    a(0) =-1a(1) =9a(2) =-128a(3) =2500a(4) =-62208a(5) =1882384a(6) =-67108864a(7) =2754990144a(8) =-128000000000

External references