Replace 2^k in binary expansion of n with 2^(2^k).

Terms

a(0) =0a(1) =2a(2) =4a(3) =6a(4) =16a(5) =18a(6) =20a(7) =22a(8) =256a(9) =258a(10) =260a(11) =262a(12) =272a(13) =274a(14) =276a(15) =278a(16) =65536a(17) =65538a(18) =65540a(19) =65542a(20) =65552a(21) =65554a(22) =65556a(23) =65558a(24) =65792a(25) =65794a(26) =65796a(27) =65798a(28) =65808a(29) =65810