Numbers whose base-10 representation has the same nonzero number of 0's and 1's.

Terms

a(0) =10a(1) =102a(2) =103a(3) =104a(4) =105a(5) =106a(6) =107a(7) =108a(8) =109a(9) =120a(10) =130a(11) =140a(12) =150a(13) =160a(14) =170a(15) =180a(16) =190a(17) =201a(18) =210a(19) =301a(20) =310a(21) =401a(22) =410a(23) =501a(24) =510a(25) =601a(26) =610a(27) =701a(28) =710a(29) =801