a(n) = n*(n-1)*8^n.

Terms

a(0) =0a(1) =0a(2) =128a(3) =3072a(4) =49152a(5) =655360a(6) =7864320a(7) =88080384a(8) =939524096a(9) =9663676416a(10) =96636764160a(11) =944892805120