(Digit 1 repeated n times) + n.

Terms

a(0) =2a(1) =13a(2) =114a(3) =1115a(4) =11116a(5) =111117a(6) =1111118a(7) =11111119a(8) =111111120a(9) =1111111121a(10) =11111111122a(11) =111111111123