A089615 Number of primes between n^2 and (n+1/5)^2.

0, 0, 0, 1, 0, 1, 0, 1, 1, 2, 0, 0, 1, 2, 2, 1, 1, 1, 1, 1, 2, 2, 0, 1, 1, 2, 2, 1, 0, 2, 2, 2, 3, 1, 3, 4, 2, 4, 2, 4, 2, 1, 1, 2, 3, 2, 2, 2, 2, 1, 3, 4, 1, 2, 2, 1, 5, 2, 2, 4, 3, 4, 1, 2, 4, 3, 3, 5, 2, 3, 2, 3, 3, 5, 5, 4, 2, 4, 5, 2, 5, 2, 4, 3, 5, 2, 6, 3, 5, 4, 6, 1, 4, 6, 5, 4, 7, 6, 6, 4, 2, 3, 4, 4, 4

Offset

1,10

Links

Table of n, a(n) for n=1..105.

Mathematica

Table[PrimePi[(n+1/5)^2]-PrimePi[n^2], {n, 110}] (* Harvey P. Dale, Nov 10 2011 *)

Prog

(PARI) pbetweensq2(n) = { for(x=1, n, c=0; for(y=floor(x)^2, (x+1/5)^2, if(isprime(y), c++) ); print1(c", ") ) }

Crossrefs

Sequence in context: A112020 A069160 A089616 * A301593 A089731 A097098

Adjacent sequences: A089612 A089613 A089614 * A089616 A089617 A089618

Keyword

easy,nonn

Author

Cino Hilliard, Dec 30 2003

Status

approved