Numbers whose base-12 representation has the same nonzero number of 1's and 3's.

Terms

a(0) =15a(1) =37a(2) =147a(3) =171a(4) =180a(5) =182a(6) =184a(7) =185a(8) =186a(9) =187a(10) =188a(11) =189a(12) =190a(13) =191a(14) =195a(15) =207a(16) =219a(17) =231a(18) =243a(19) =255a(20) =267a(21) =279a(22) =303a(23) =325a(24) =433a(25) =444a(26) =446a(27) =448a(28) =449a(29) =450