Positions of ones in binary expansion of arctan(1/2)/Pi.

Terms

a(0) =3a(1) =6a(2) =8a(3) =9a(4) =10a(5) =13a(6) =21a(7) =23a(8) =27a(9) =28a(10) =29a(11) =31a(12) =32a(13) =35a(14) =36a(15) =37a(16) =39a(17) =40a(18) =41a(19) =42a(20) =43a(21) =46a(22) =47a(23) =52a(24) =57a(25) =58a(26) =61a(27) =62a(28) =65a(29) =67