a(n) = 8*9^n - 7*8^n.

Terms

a(0) =1a(1) =16a(2) =200a(3) =2248a(4) =23816a(5) =243016a(6) =2416520a(7) =23583688a(8) =226933256a(9) =2159839816a(10) =20378082440a(11) =190918934728