%I

%S 2,11,31,97,12251,564163

%N Numbers n such that there are a prime number of primes less than 2^n.

%C The next entry is greater than 2^44 as 2^45 exceeds The Nth Prime Page.

%o (PARI) primeslessxn2(n,p) = \primes < p^n if prime { sr=0; for(x=0,n, y=pi(p^x); if(y<>0,sr+=1.0/y); if(isprime(y),print1(y",")); ); print(); print(sr) }

%K nonn

%O 1,1

%A _Cino Hilliard_, Oct 27 2003