a(n) = round(log_2(n)*2^n/n).

Terms

a(0) =0a(1) =2a(2) =4a(3) =8a(4) =15a(5) =28a(6) =51a(7) =96a(8) =180a(9) =340a(10) =644a(11) =1224a(12) =2332a(13) =4456a(14) =8535a(15) =16384a(16) =31515a(17) =60729a(18) =117218a(19) =226594a(20) =438636a(21) =850191a(22) =1649843a(23) =3205121a(24) =6232878a(25) =12132353a(26) =23636674a(27) =46088018a(28) =89934782a(29) =175624455