a(n) = (n - 4)*n! for n>=0.

Terms

a(0) =-4a(1) =-3a(2) =-4a(3) =-6a(4) =0a(5) =120a(6) =1440a(7) =15120a(8) =161280a(9) =1814400a(10) =21772800a(11) =279417600a(12) =3832012800a(13) =56043187200a(14) =871782912000