Numbers whose base-7 representation has the same nonzero number of 0's and 1's.

Terms

a(0) =7a(1) =51a(2) =52a(3) =53a(4) =54a(5) =55a(6) =63a(7) =70a(8) =77a(9) =84a(10) =91a(11) =99a(12) =105a(13) =148a(14) =154a(15) =197a(16) =203a(17) =246a(18) =252a(19) =295a(20) =301a(21) =344a(22) =350a(23) =359a(24) =360a(25) =361a(26) =362a(27) =363a(28) =366a(29) =367