a(n) = 10^n - 3^n + 1.

Terms

a(0) =1a(1) =8a(2) =92a(3) =974a(4) =9920a(5) =99758a(6) =999272a(7) =9997814a(8) =99993440a(9) =999980318a(10) =9999940952a(11) =99999822854a(12) =999999468560