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

A332187

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

Terms

    a(0) =7a(1) =878a(2) =88788a(3) =8887888a(4) =888878888a(5) =88888788888

External references