11^n+9^n-1^n.

Terms

a(0) =1a(1) =19a(2) =201a(3) =2059a(4) =21201a(5) =220099a(6) =2303001a(7) =24270139a(8) =257405601a(9) =2745368179a(10) =29424209001a(11) =316692730219