Numbers with no 3's in base-4 expansion.

Terms

a(0) =0a(1) =1a(2) =2a(3) =4a(4) =5a(5) =6a(6) =8a(7) =9a(8) =10a(9) =16a(10) =17a(11) =18a(12) =20a(13) =21a(14) =22a(15) =24a(16) =25a(17) =26a(18) =32a(19) =33a(20) =34a(21) =36a(22) =37a(23) =38a(24) =40a(25) =41a(26) =42a(27) =64a(28) =65a(29) =66