Numbers n whose binary expansion does not begin with 11.

Terms

a(0) =0a(1) =1a(2) =2a(3) =4a(4) =5a(5) =8a(6) =9a(7) =10a(8) =11a(9) =16a(10) =17a(11) =18a(12) =19a(13) =20a(14) =21a(15) =22a(16) =23a(17) =32a(18) =33a(19) =34a(20) =35a(21) =36a(22) =37a(23) =38a(24) =39a(25) =40a(26) =41a(27) =42a(28) =43a(29) =44