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

A332189

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

Terms

    a(0) =9a(1) =898a(2) =88988a(3) =8889888a(4) =888898888a(5) =88888988888

External references