Numbers whose base-7 representation has the same nonzero number of 1's and 5's.

Terms

a(0) =12a(1) =36a(2) =54a(3) =68a(4) =75a(5) =82a(6) =84a(7) =86a(8) =87a(9) =88a(10) =90a(11) =96a(12) =110a(13) =134a(14) =159a(15) =183a(16) =208a(17) =232a(18) =246a(19) =252a(20) =254a(21) =255a(22) =256a(23) =258a(24) =260a(25) =267a(26) =274a(27) =288a(28) =306a(29) =330