Numbers whose base-9 representation has the same nonzero number of 1's and 6's.

Terms

a(0) =15a(1) =55a(2) =87a(3) =105a(4) =114a(5) =123a(6) =132a(7) =135a(8) =137a(9) =138a(10) =139a(11) =140a(12) =142a(13) =143a(14) =150a(15) =159a(16) =177a(17) =217a(18) =258a(19) =298a(20) =339a(21) =379a(22) =420a(23) =460a(24) =487a(25) =495a(26) =497a(27) =498a(28) =499a(29) =500