10^n-6^n+1.

Terms

a(0) =1a(1) =5a(2) =65a(3) =785a(4) =8705a(5) =92225a(6) =953345a(7) =9720065a(8) =98320385a(9) =989922305a(10) =9939533825a(11) =99637202945a(12) =997823217665