OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
Eric Weisstein's World of Mathematics, Quadratic Nonresidue.
MATHEMATICA
Select[Range[14000], Min @ Complement[Range[# - 1], Mod[Range[#/2]^2, #]] == 13 &] (* Amiram Eldar, Oct 31 2020 *)
PROG
(PARI) residue(n, m)=local(r); r=0; for(i=1, floor(m/2), if(i^2%m==n, r=1)); r
isA025025(n)=local(a); a=1; forprime(p=2, 11, a=a && residue(p, n)); a=a && !residue(13, n); a \\ Michael B. Porter, Apr 30 2010
(PARI) is(n)=issquare(Mod(2, n)) && issquare(Mod(3, n)) && issquare(Mod(5, n)) && issquare(Mod(7, n)) && issquare(Mod(11, n)) && !issquare(Mod(13, n)) \\ Charles R Greathouse IV, Jan 24 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved