a(n) = 3*(10^(2n+1)-1)/9 + 3*10^n.A332136a(n) = 3*(10^(2n+1)-1)/9 + 3*10^n.Terms a(0) =6a(1) =363a(2) =33633a(3) =3336333a(4) =333363333a(5) =33333633333External referencesoeis: A332136