a(n) = (10^(2*n+1) - 1)/9 + 8*10^n.

A332119

a(n) = (10^(2*n+1) - 1)/9 + 8*10^n.

Terms

    a(0) =9a(1) =191a(2) =11911a(3) =1119111a(4) =111191111a(5) =11111911111

External references