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

Terms

a(0) =1a(1) =18a(2) =99a(3) =756a(4) =6597a(5) =59094a(6) =531495a(7) =4783032a(8) =43046793a(9) =387420570a(10) =3486784491a(11) =31381059708a(12) =282429536589