Numbers whose base-9 representation has the same number of 0's and 1's.

Terms

a(0) =2a(1) =3a(2) =4a(3) =5a(4) =6a(5) =7a(6) =8a(7) =9a(8) =20a(9) =21a(10) =22a(11) =23a(12) =24a(13) =25a(14) =26a(15) =29a(16) =30a(17) =31a(18) =32a(19) =33a(20) =34a(21) =35a(22) =38a(23) =39a(24) =40a(25) =41a(26) =42a(27) =43a(28) =44a(29) =47