a(n) = 8^n - 7^n - 6^n - 5^n + 3*4^n.

Terms

a(0) =1a(1) =2a(2) =2a(3) =20a(4) =542a(5) =8132a(6) =94502a(7) =964700a(8) =9138782a(9) =82619732a(10) =724180502a(11) =6213565580a(12) =52507598222a(13) =438786732932