n times (n 1's): a(n) = n*(10^n - 1)/9.

A053422

n times (n 1's): a(n) = n*(10^n - 1)/9.

Terms

    a(0) =0a(1) =1a(2) =22a(3) =333a(4) =4444a(5) =55555a(6) =666666a(7) =7777777a(8) =88888888a(9) =999999999a(10) =11111111110a(11) =122222222221

External references