Numbers whose base-10 representation has the same nonzero number of 3's and 6's.

Terms

a(0) =36a(1) =63a(2) =136a(3) =163a(4) =236a(5) =263a(6) =306a(7) =316a(8) =326a(9) =346a(10) =356a(11) =360a(12) =361a(13) =362a(14) =364a(15) =365a(16) =367a(17) =368a(18) =369a(19) =376a(20) =386a(21) =396a(22) =436a(23) =463a(24) =536a(25) =563a(26) =603a(27) =613a(28) =623a(29) =630