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
Harvey P. Dale, Table of n, a(n) for n = 1..3000
Wikipedia, Integer square root
MATHEMATICA
Select[Prime[Range[100]], !PrimeQ[#-Floor[Sqrt[#]]^2]&] (* Harvey P. Dale, May 29 2024 *)
PROG
(PARI) { forprime(p=2, 2000, isr = sqrtint(p); Rem = p - isr*isr; if (!isprime(Rem), print1(p, ", ") ) ) }
CROSSREFS
KEYWORD
nonn
AUTHOR
Harry J. Smith, Dec 07 2007
STATUS
approved