Numbers whose base-7 representation has the same number of 1's and 6's.

Terms

a(0) =0a(1) =2a(2) =3a(3) =4a(4) =5a(5) =13a(6) =14a(7) =16a(8) =17a(9) =18a(10) =19a(11) =21a(12) =23a(13) =24a(14) =25a(15) =26a(16) =28a(17) =30a(18) =31a(19) =32a(20) =33a(21) =35a(22) =37a(23) =38a(24) =39a(25) =40a(26) =43a(27) =55a(28) =69a(29) =76