Numbers whose base-9 representation has the same number of 1's and 2's.

Terms

a(0) =0a(1) =3a(2) =4a(3) =5a(4) =6a(5) =7a(6) =8a(7) =11a(8) =19a(9) =27a(10) =30a(11) =31a(12) =32a(13) =33a(14) =34a(15) =35a(16) =36a(17) =39a(18) =40a(19) =41a(20) =42a(21) =43a(22) =44a(23) =45a(24) =48a(25) =49a(26) =50a(27) =51a(28) =52a(29) =53