Write n in binary, reverse bits, subtract 1, divide by 2.

Terms

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