login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A195007 Number of primes in the range (n*sqrt(n-1), (n+1)*sqrt(n)]. 1
1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 1, 2, 1, 1, 1, 1, 3, 2, 0, 1, 2, 1, 2, 1, 2, 1, 2, 2, 2, 1, 0, 3, 2, 1, 2, 1, 3, 2, 1, 1, 3, 0, 2, 2, 2, 1, 2, 2, 2, 1, 2, 2, 3, 1, 3, 1, 2, 2, 1, 2, 1, 1, 2, 3, 2, 2, 4, 1, 2, 2, 2, 3, 1, 2, 1, 2, 3, 2, 2, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

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

EXAMPLE

a(1)=1`because 1*sqrt(1-1)<(prime 2)<=(1+1)*sqrt(1),

a(2)=1 because 2*sqrt(2-1)<(prime 3)<=(2+1)*sqrt(2).

MATHEMATICA

Table[PrimePi[(n+1)*Sqrt[n]] - PrimePi[n*Sqrt[n-1]], {n, 100}] (* T. D. Noe, Sep 14 2011 *)

CROSSREFS

Cf. A006005, A192454.

Sequence in context: A168201 A263000 A075774 * A276947 A178085 A078572

Adjacent sequences:  A195004 A195005 A195006 * A195008 A195009 A195010

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Sep 07 2011

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 13 08:18 EDT 2022. Contains 356079 sequences. (Running on oeis4.)