a(n) = repeating period of the digital roots of the sequence {m^n, m=1,2,3...}.

Terms

a(0) =1a(1) =124875a(2) =9a(3) =147a(4) =157842a(5) =9a(6) =174a(7) =18a(8) =9a(9) =1a(10) =124875a(11) =9a(12) =147a(13) =157842a(14) =9a(15) =174a(16) =18a(17) =9a(18) =1a(19) =124875a(20) =9a(21) =147a(22) =157842a(23) =9a(24) =174a(25) =18a(26) =9a(27) =1a(28) =124875a(29) =9