a(n) = (4*10^n - 13)/9.

A173770

a(n) = (4*10^n - 13)/9.

Terms

    a(0) =3a(1) =43a(2) =443a(3) =4443a(4) =44443a(5) =444443a(6) =4444443a(7) =44444443a(8) =444444443a(9) =4444444443a(10) =44444444443a(11) =444444444443

External references