1 concatenated with n n's concatenated with 1.

A137465

1 concatenated with n n's concatenated with 1.

Terms

    a(0) =111a(1) =1221a(2) =13331a(3) =144441a(4) =1555551a(5) =16666661a(6) =177777771a(7) =1888888881a(8) =19999999991

External references