a(n) = n*9^(n-1).

Terms

a(0) =1a(1) =18a(2) =243a(3) =2916a(4) =32805a(5) =354294a(6) =3720087a(7) =38263752a(8) =387420489a(9) =3874204890a(10) =38354628411a(11) =376572715308