Numbers whose base-7 representation has the same nonzero number of 1's and 6's.

Terms

a(0) =13a(1) =43a(2) =55a(3) =69a(4) =76a(5) =83a(6) =90a(7) =91a(8) =93a(9) =94a(10) =95a(11) =96a(12) =111a(13) =141a(14) =160a(15) =190a(16) =209a(17) =239a(18) =258a(19) =288a(20) =295a(21) =301a(22) =303a(23) =304a(24) =305a(25) =306a(26) =309a(27) =316a(28) =323a(29) =330