Number of rationals in [0, 1) consisting just of repeating bits of period at most n.

Terms

a(0) =1a(1) =3a(2) =9a(3) =21a(4) =51a(5) =105a(6) =231a(7) =471a(8) =975a(9) =1965a(10) =4011a(11) =8031a(12) =16221a(13) =32475a(14) =65205a(15) =130485a(16) =261555a(17) =523131a(18) =1047417a(19) =2094957a(20) =4191975a(21) =8384229a(22) =16772835a(23) =33545715a(24) =67100115a(25) =134200785a(26) =268418001a(27) =536837061a(28) =1073707971a(29) =2147415981