Numbers whose binary expansion is 1xy100...0 where x,y = 0 or 1.

Terms

a(0) =9a(1) =11a(2) =13a(3) =15a(4) =18a(5) =22a(6) =26a(7) =30a(8) =36a(9) =44a(10) =52a(11) =60a(12) =72a(13) =88a(14) =104a(15) =120a(16) =144a(17) =176a(18) =208a(19) =240a(20) =288a(21) =352a(22) =416a(23) =480a(24) =576a(25) =704a(26) =832a(27) =960a(28) =1152a(29) =1408