a(n) = 9^n mod 5^n.

Terms

a(0) =0a(1) =4a(2) =6a(3) =104a(4) =311a(5) =2799a(6) =191a(7) =17344a(8) =77971a(9) =701739a(10) =456276a(11) =33403359a(12) =202973981a(13) =361922079a(14) =815892461a(15) =19550063399a(16) =145432992466a(17) =88193807194