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

Terms

a(0) =0a(1) =2a(2) =5a(3) =8a(4) =15a(5) =28a(6) =52a(7) =96a(8) =181a(9) =341a(10) =645a(11) =1224a(12) =2332a(13) =4456a(14) =8535a(15) =16384a(16) =31515a(17) =60729a(18) =117218a(19) =226594a(20) =438637a(21) =850192a(22) =1649843a(23) =3205122a(24) =6232879a(25) =12132353a(26) =23636674a(27) =46088019a(28) =89934783a(29) =175624456