a(n) = 7*10^n + 1.

Terms

a(0) =8a(1) =71a(2) =701a(3) =7001a(4) =70001a(5) =700001a(6) =7000001a(7) =70000001a(8) =700000001a(9) =7000000001a(10) =70000000001a(11) =700000000001