10^n-4^n+1^n.

Terms

a(0) =1a(1) =7a(2) =85a(3) =937a(4) =9745a(5) =98977a(6) =995905a(7) =9983617a(8) =99934465a(9) =999737857a(10) =9998951425a(11) =99995805697a(12) =999983222785