28192750domain: NAppears in sequencesNumber of primes <= 2^n.at n=29A007053Number of primes < 2^prime(n).at n=9A086690Reduced numerators of the ratios of Pi(2^(n+1))/Pi(2^(n)).at n=27A157301Number of primes less than 2^n.at n=28A185192