

A192064


Number of primes in the range [2^nn, 2^n].


2



0, 1, 2, 2, 1, 2, 2, 1, 1, 2, 2, 1, 2, 2, 1, 0, 1, 3, 3, 2, 3, 3, 2, 2, 2, 0, 1, 0, 0, 1, 0, 2, 2, 2, 0, 1, 3, 2, 0, 2, 0, 2, 3, 0, 1, 0, 1, 0, 0, 0, 2, 0, 1, 0, 2, 1, 3, 3, 2, 1, 0, 3, 1, 1, 1, 1, 2, 5, 1, 1, 1, 0, 0, 1, 3, 0, 2, 2, 1
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OFFSET

0,3


LINKS

Table of n, a(n) for n=0..78.


EXAMPLE

a(0)=0 because [2^00, 2^0]=[1, 1],
a(1)=1 because 2 in range [2^11, 2^1]=[1,2],
a(2)=2 because 2, 3 in range [2^22, 2^2]=[2, 4],
a(3)=2 because 5, 7 in range [2^33, 2^3]=[5, 8],
a(4)=1 because 13 in range [2^44, 2^4]=[12, 16],
a(5)=2 because 29, 31 in range [2^55, 2^5]=[27, 32].


MAPLE

A192064 := proc(n) numtheory[pi](2^n)numtheory[pi](2^nn1) ; end proc: # R. J. Mathar, Jul 07 2011


PROG

(PARI) a(n)=sum(k=2^nn, 2^n, isprime(k)) \\ Charles R Greathouse IV, Jul 03 2011


CROSSREFS

Sequence in context: A232628 A087889 A285110 * A225182 A014710 A055174
Adjacent sequences: A192061 A192062 A192063 * A192065 A192066 A192067


KEYWORD

nonn


AUTHOR

JuriStepan Gerasimov, Jul 03 2011


EXTENSIONS

Corrected and extended by Charles R Greathouse IV, Jul 03 2011


STATUS

approved



