a(n) = 2*(10^(2n+1)-1)/9 + 6*10^n.

A332128

a(n) = 2*(10^(2n+1)-1)/9 + 6*10^n.

Terms

    a(0) =8a(1) =282a(2) =22822a(3) =2228222a(4) =222282222a(5) =22222822222

External references