A192227 - OEIS

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A192227

Number of primes in the range (n - 2*sqrt(sqrt(n)), n].

0, 1, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 2, 2, 1, 1, 2, 1, 2, 2, 2, 1, 2, 1, 1, 1, 1, 0, 1, 1, 2, 2, 2, 1, 1, 0, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 2, 2, 2, 1

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OFFSET

1,3

COMMENTS

a(n) is probably positive for all n > 191913030. - Charles R Greathouse IV, Jul 01 2011

LINKS

Table of n, a(n) for n=1..86.

FORMULA

Conjecturally, a(n) ~ 2*n^(1/4)/log n. - Charles R Greathouse IV, Jul 01 2011

MAPLE

A192227 := proc(n) local nhi, nlo ; nhi := n ; nlo := floor( n-2*root[4](n)) ; numtheory[pi](nhi)-numtheory[pi](nlo) ; end proc; # R. J. Mathar, Jul 12 2011

MATHEMATICA

Table[PrimePi[n]-PrimePi[n-2*Sqrt[Sqrt[n]]], {n, 90}] (* Harvey P. Dale, Feb 24 2018 *)

CROSSREFS

Cf. A188817, A189025, A192226.

Sequence in context: A262742 A360078 A027354 * A102673 A085297 A080972

Adjacent sequences: A192224 A192225 A192226 * A192228 A192229 A192230

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Jun 26 2011

STATUS

approved