a(n) = n*9^n.

Terms

a(0) =0a(1) =9a(2) =162a(3) =2187a(4) =26244a(5) =295245a(6) =3188646a(7) =33480783a(8) =344373768a(9) =3486784401a(10) =34867844010a(11) =345191655699