a(n) = (5*10^n - 23)/9.

A173802

a(n) = (5*10^n - 23)/9.

Terms

    a(0) =3a(1) =53a(2) =553a(3) =5553a(4) =55553a(5) =555553a(6) =5555553a(7) =55555553a(8) =555555553a(9) =5555555553a(10) =55555555553a(11) =555555555553

External references