a(n) = n*(2*(n-1))! for n > 0, a(0) = 1.

A327882

a(n) = n*(2*(n-1))! for n > 0, a(0) = 1.

Terms

    a(0) =1a(1) =1a(2) =4a(3) =72a(4) =2880a(5) =201600a(6) =21772800a(7) =3353011200a(8) =697426329600

External references