Numbers whose base-7 representation has the same nonzero number of 5's and 6's.

Terms

a(0) =41a(1) =47a(2) =90a(3) =96a(4) =139a(5) =145a(6) =188a(7) =194a(8) =237a(9) =243a(10) =251a(11) =258a(12) =265a(13) =272a(14) =279a(15) =287a(16) =288a(17) =289a(18) =290a(19) =291a(20) =299a(21) =306a(22) =313a(23) =320a(24) =327a(25) =329a(26) =330a(27) =331a(28) =332a(29) =333