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

A332165

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

Terms

    a(0) =5a(1) =656a(2) =66566a(3) =6665666a(4) =666656666a(5) =66666566666

External references