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

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

%S 2,2,3,2,2,2,3,3,2,2,2,2,3,3,2,1,2,2,4,3,4,3,3,2,3,4,5,5,4,3,2,3,3,2,

%T 2,3,3,3,3,3,3,2,3,4,4,3,1,3,4,4,4,3,2,2,3,4,4,4,5,3,3,1,3,4,4,3,2,2,

%U 3,3,4,3,3,3,3,3,3,3,3,2,2,2,3,3,4,3,3,4,4,4,3,2,3,3,3,3,2,2,2,2,2,2,4,4,4

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

%C a(n) = A000720(A098389(n)) - A000720(A098390(n)-1);

%C A098398(n) <= A098396(n) <= a(n) <= A097935(n).

%e a(10) = #{p prime: A098389(10) <= p <= A098390(10)} =

%e = #{p prime: 25 <= p <= 33} = #{29,31} = 2.

%K nonn

%O 1,1

%A _Reinhard Zumkeller_, Sep 06 2004