login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A135932 Primes whose integer square root remainder is also prime. 6
3, 7, 11, 19, 23, 41, 43, 47, 67, 71, 83, 103, 107, 113, 149, 151, 157, 163, 167, 199, 227, 263, 269, 331, 337, 347, 353, 419, 431, 443, 487, 491, 503, 521, 587, 593, 599, 607, 613, 617, 619, 683, 719, 787, 797, 821, 827, 907, 911, 919, 929, 937, 941, 947 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The integer square root of an integer x >= 0 can be defined as floor(sqrt(x)) and the remainder of this as x - (floor(sqrt(x)))^2.

LINKS

Table of n, a(n) for n=1..54.

Wikipedia, Integer square root

MATHEMATICA

f[n_]:=n-(Floor[Sqrt[n]])^2; lst={}; Do[p=Prime[n]; If[PrimeQ[f[p]], AppendTo[lst, p]], {n, 7!}]; lst (* Vladimir Joseph Stephan Orlovsky, Feb 25 2010 *)

PROG

(PARI) { forprime(p=2, 2000, isr = sqrtint(p); Rem = p - isr*isr; if (isprime(Rem), print1(p, ", ") ) ) }

CROSSREFS

Sequence in context: A018805 A191037 A292083 * A231847 A105876 A141101

Adjacent sequences:  A135929 A135930 A135931 * A135933 A135934 A135935

KEYWORD

nonn

AUTHOR

Harry J. Smith, Dec 07 2007

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 15 11:35 EST 2018. Contains 317238 sequences. (Running on oeis4.)