a(n) = 8*9^n+1.

Terms

a(0) =9a(1) =73a(2) =649a(3) =5833a(4) =52489a(5) =472393a(6) =4251529a(7) =38263753a(8) =344373769a(9) =3099363913a(10) =27894275209a(11) =251048476873