Numbers having two 9's in base 10.

Terms

a(0) =99a(1) =199a(2) =299a(3) =399a(4) =499a(5) =599a(6) =699a(7) =799a(8) =899a(9) =909a(10) =919a(11) =929a(12) =939a(13) =949a(14) =959a(15) =969a(16) =979a(17) =989a(18) =990a(19) =991a(20) =992a(21) =993a(22) =994a(23) =995a(24) =996a(25) =997a(26) =998a(27) =1099a(28) =1199a(29) =1299