Numbers whose set of base-4 digits is a subset of {1,2}.

Terms

a(0) =1a(1) =2a(2) =5a(3) =6a(4) =9a(5) =10a(6) =21a(7) =22a(8) =25a(9) =26a(10) =37a(11) =38a(12) =41a(13) =42a(14) =85a(15) =86a(16) =89a(17) =90a(18) =101a(19) =102a(20) =105a(21) =106a(22) =149a(23) =150a(24) =153a(25) =154a(26) =165a(27) =166a(28) =169a(29) =170