a(n) = 10^n + 9.

Terms

a(0) =10a(1) =19a(2) =109a(3) =1009a(4) =10009a(5) =100009a(6) =1000009a(7) =10000009a(8) =100000009a(9) =1000000009a(10) =10000000009a(11) =100000000009