a(n) = (10^(2n+1)-1)/9 + 10^n.A332112a(n) = (10^(2n+1)-1)/9 + 10^n.Terms a(0) =2a(1) =121a(2) =11211a(3) =1112111a(4) =111121111a(5) =11111211111External referencesoeis: A332112