Numbers whose binary expansion does not begin 101.

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =4a(5) =6a(6) =7a(7) =8a(8) =9a(9) =12a(10) =13a(11) =14a(12) =15a(13) =16a(14) =17a(15) =18a(16) =19a(17) =24a(18) =25a(19) =26a(20) =27a(21) =28a(22) =29a(23) =30a(24) =31a(25) =32a(26) =33a(27) =34a(28) =35a(29) =36