a(n) = (7*10^n + 11)/9 for n > 0.

Terms

a(0) =9a(1) =79a(2) =779a(3) =7779a(4) =77779a(5) =777779a(6) =7777779a(7) =77777779a(8) =777777779a(9) =7777777779a(10) =77777777779a(11) =777777777779