a(n) = n^n - n.

Terms

a(0) =1a(1) =0a(2) =2a(3) =24a(4) =252a(5) =3120a(6) =46650a(7) =823536a(8) =16777208a(9) =387420480a(10) =9999999990a(11) =285311670600