login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A089616 Number of primes between n^2 and (n+1/6)^2. 1
0, 0, 0, 1, 0, 1, 0, 0, 1, 2, 0, 0, 1, 2, 2, 1, 1, 0, 1, 1, 1, 2, 0, 1, 1, 2, 1, 1, 0, 1, 2, 2, 3, 1, 2, 4, 2, 3, 2, 4, 1, 1, 1, 1, 3, 2, 2, 2, 2, 1, 2, 4, 1, 2, 2, 1, 4, 2, 2, 3, 3, 4, 1, 2, 4, 3, 2, 3, 1, 3, 2, 2, 3, 3, 3, 4, 2, 3, 3, 1, 5, 2, 3, 3, 5, 2, 5, 3, 4, 4, 5, 1, 3, 6, 4, 4, 7, 5, 5, 2, 2, 3, 4, 3, 4 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,10

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

MAPLE

seq(numtheory:-pi(floor((n+1/6)^2))-numtheory:-pi(n^2), n=1..200); # Robert Israel, Jan 02 2018

MATHEMATICA

Table[PrimePi[(n+1/6)^2]-PrimePi[n^2], {n, 110}] (* Harvey P. Dale, Sep 17 2013 *)

PROG

(PARI) pbetweensq2(n) = { for(x=1, n, c=0; for(y=floor(x)^2, (x+1/6)^2, if(isprime(y), c++) ); print1(c", ") ) }

(PARI) a(n) = primepi((n+1/6)^2) - primepi(n^2); \\ Michel Marcus, Jan 03 2018

CROSSREFS

Sequence in context: A277937 A112020 A069160 * A089615 A301593 A089731

Adjacent sequences:  A089613 A089614 A089615 * A089617 A089618 A089619

KEYWORD

easy,nonn,look

AUTHOR

Cino Hilliard, Dec 31 2003

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 5 02:11 EDT 2020. Contains 333238 sequences. (Running on oeis4.)