Period of powers of 11 mod 10^n.

Terms

a(0) =10a(1) =50a(2) =500a(3) =5000a(4) =50000a(5) =500000a(6) =5000000a(7) =50000000a(8) =500000000a(9) =5000000000a(10) =50000000000a(11) =500000000000