a(n)=Sum(d|n)(10^(n-d)).

Terms

a(0) =1a(1) =11a(2) =101a(3) =1101a(4) =10001a(5) =111001a(6) =1000001a(7) =11010001a(8) =101000001a(9) =1100100001a(10) =10000000001a(11) =111101000001