a(n) = (10^(2n+1)-1)/3 + 2*10^n.

A332135

a(n) = (10^(2n+1)-1)/3 + 2*10^n.

Terms

    a(0) =5a(1) =353a(2) =33533a(3) =3335333a(4) =333353333a(5) =33333533333

External references