Numbers whose base-7 representation has the same number of 0's and 4's.

Terms

a(0) =1a(1) =2a(2) =3a(3) =5a(4) =6a(5) =8a(6) =9a(7) =10a(8) =12a(9) =13a(10) =15a(11) =16a(12) =17a(13) =19a(14) =20a(15) =22a(16) =23a(17) =24a(18) =26a(19) =27a(20) =28a(21) =36a(22) =37a(23) =38a(24) =40a(25) =41a(26) =43a(27) =44a(28) =45a(29) =47