a(n) = (2n)!/n! - (2n)!/(n-1)!.

A119837

a(n) = (2n)!/n! - (2n)!/(n-1)!.

Terms

    a(0) =1a(1) =0a(2) =-12a(3) =-240a(4) =-5040a(5) =-120960a(6) =-3326400a(7) =-103783680a(8) =-3632428800a(9) =-141145804800

External references