Number of primes between n and 2^n exclusive.

Terms

a(0) =0a(1) =1a(2) =2a(3) =4a(4) =8a(5) =15a(6) =27a(7) =50a(8) =93a(9) =168a(10) =304a(11) =559a(12) =1022a(13) =1894a(14) =3506a(15) =6536a(16) =12244a(17) =22993a(18) =43382a(19) =82017a(20) =155603a(21) =295939a(22) =564154a(23) =1077862a(24) =2063680a(25) =3957800a(26) =7603544a(27) =14630834a(28) =28192740a(29) =54400018