Numbers whose base-4 and base-7 expansions have no digits in common.

Terms

a(0) =4a(1) =5a(2) =6a(3) =8a(4) =10a(5) =11a(6) =12a(7) =15a(8) =16a(9) =17a(10) =19a(11) =20a(12) =21a(13) =24a(14) =25a(15) =26a(16) =32a(17) =33a(18) =34a(19) =38a(20) =39a(21) =40a(22) =41a(23) =42a(24) =43a(25) =46a(26) =47a(27) =48a(28) =60a(29) =62