login
Number of primes that are not less than prime(n)-Log2(Log2(prime(n))) and not greater than prime(n)+Log2(Log2(prime(n))), where Log2=A000523.
2

%I #3 Mar 30 2012 18:50:45

%S 1,1,1,1,1,1,2,2,1,2,2,1,2,2,1,1,2,2,1,2,2,1,1,1,1,2,2,2,2,1,1,1,2,2,

%T 2,2,1,1,1,1,2,2,2,2,2,2,1,1,2,2,1,2,2,1,1,1,2,2,1,2,2,1,1,2,2,1,1,1,

%U 2,2,1,1,1,1,1,1,1,1,1,1,2,2,2,2,1,1,1,1,2,2,1,1,1,1,1,1,1,2,2,1,1,1,1,2,2

%N Number of primes that are not less than prime(n)-Log2(Log2(prime(n))) and not greater than prime(n)+Log2(Log2(prime(n))), where Log2=A000523.

%C a(n) = A000720(A098392(n)) - A000720(A098393(n)-1);

%C a(n) <= A098396(n) <= A098397(n) <= A097935(n);

%C a(n)<=2 for n<=6543; a(6544)=#{2^16+1=65537,65539,65543}=3.

%e a(10) = #{p prime: A098392(10) <= p <= A098393(10)} =

%e = #{p prime: 27 <= p <= 31} = #{29,31} = 2.

%K nonn

%O 1,7

%A _Reinhard Zumkeller_, Sep 06 2004