%I #15 Oct 31 2020 04:35:48
%S 71,142,191,239,241,359,382,409,431,478,482,599,601,718,769,818,862,
%T 911,1031,1198,1202,1249,1321,1439,1489,1538,1609,1822,1871,2039,2062,
%U 2089,2111,2161,2281,2498,2591,2642,2711,2878,2879,2978,3001,3119,3121,3169
%N Numbers whose least quadratic nonresidue (A020649) is 7.
%H Amiram Eldar, <a href="/A025023/b025023.txt">Table of n, a(n) for n = 1..10000</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/QuadraticNonresidue.html">Quadratic Nonresidue</a>.
%t Select[Range[3200], Min @ Complement[Range[# - 1], Mod[Range[#/2]^2, #]] == 7 &] (* _Amiram Eldar_, Oct 31 2020 *)
%o (PARI) residue(n,m)=local(r);r=0;for(i=1,floor(m/2),if(i^2%m==n,r=1));r
%o isA025023(n)=residue(2,n) && residue(3,n) && residue(5,n) && !residue(7,n) \\ _Michael B. Porter_, Apr 19 2010
%o (PARI) is(n)=issquare(Mod(2,n)) && issquare(Mod(3,n)) && issquare(Mod(5,n)) && !issquare(Mod(7,n)) \\ _Charles R Greathouse IV_, Jan 24 2020
%Y Cf. A020649, A025020, A025021, A025022, A025024, A025025, A025026, A025027, A025028, A025029.
%K nonn
%O 1,1
%A _David W. Wilson_