Numbers whose base-7 representation has the same nonzero number of 2's and 4's.

Terms

a(0) =18a(1) =30a(2) =67a(3) =79a(4) =102a(5) =109a(6) =123a(7) =126a(8) =127a(9) =129a(10) =131a(11) =132a(12) =137a(13) =144a(14) =165a(15) =177a(16) =198a(17) =205a(18) =210a(19) =211a(20) =213a(21) =215a(22) =216a(23) =219a(24) =233a(25) =240a(26) =263a(27) =275a(28) =312a(29) =324