Number of primes between n and 2^n inclusive.

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =4a(5) =9a(6) =15a(7) =28a(8) =50a(9) =93a(10) =168a(11) =305a(12) =559a(13) =1023a(14) =1894a(15) =3506a(16) =6536a(17) =12245a(18) =22993a(19) =43383a(20) =82017a(21) =155603a(22) =295939a(23) =564155a(24) =1077862a(25) =2063680a(26) =3957800a(27) =7603544a(28) =14630834a(29) =28192741