10^n-5^n+1.

Terms

a(0) =1a(1) =6a(2) =76a(3) =876a(4) =9376a(5) =96876a(6) =984376a(7) =9921876a(8) =99609376a(9) =998046876a(10) =9990234376a(11) =99951171876a(12) =999755859376