a(n) = floor(2^(n-1)/n).

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =5a(6) =9a(7) =16a(8) =28a(9) =51a(10) =93a(11) =170a(12) =315a(13) =585a(14) =1092a(15) =2048a(16) =3855a(17) =7281a(18) =13797a(19) =26214a(20) =49932a(21) =95325a(22) =182361a(23) =349525a(24) =671088a(25) =1290555a(26) =2485513a(27) =4793490a(28) =9256395a(29) =17895697