a(n+2) = (2n+3)*a(n+1) + (n+1)^2*a(n).

Terms

a(0) =-2a(1) =1a(2) =1a(3) =9a(4) =72a(5) =792a(6) =10512a(7) =165168a(8) =2992608a(9) =61445088a(10) =1409857920a(11) =35751525120a(12) =992877886080