Numbers whose base-7 representation has the same number of 3's and 6's.

Terms

a(0) =0a(1) =1a(2) =2a(3) =4a(4) =5a(5) =7a(6) =8a(7) =9a(8) =11a(9) =12a(10) =14a(11) =15a(12) =16a(13) =18a(14) =19a(15) =27a(16) =28a(17) =29a(18) =30a(19) =32a(20) =33a(21) =35a(22) =36a(23) =37a(24) =39a(25) =40a(26) =45a(27) =49a(28) =50a(29) =51