a(n) = n! - n^8.

Terms

a(0) =1a(1) =0a(2) =-254a(3) =-6555a(4) =-65512a(5) =-390505a(6) =-1678896a(7) =-5759761a(8) =-16736896a(9) =-42683841a(10) =-96371200a(11) =-174442081a(12) =49019904a(13) =5411290079a(14) =85702502144