%I #18 Feb 16 2025 08:32:35
%S 3,4,5,6,8,9,10,11,12,13,15,16,18,19,20,21,22,24,25,26,27,28,29,30,32,
%T 33,35,36,37,38,39,40,42,43,44,45,48,50,51,52,53,54,55,56,57,58,59,60,
%U 61,63,64,65,66,67,68,69,70,72,74,75,76,77,78,80,81,83,84,85,86,87,88,90,91,92
%N Numbers whose least quadratic nonresidue (A020649) is 2.
%H Amiram Eldar, <a href="/A025020/b025020.txt">Table of n, a(n) for n = 1..10000</a>
%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/QuadraticNonresidue.html">Quadratic Nonresidue</a>.
%t Select[Range[100], Min @ Complement[Range[# - 1], Mod[Range[#/2]^2, #]] == 2 &] (* _Amiram Eldar_, Oct 31 2020 *)
%o (PARI) isA025020(n)={local(r);r=1;for(m=1,n-1,if(m^2%n==2,r=0));r} \\ _Michael B. Porter_, Apr 16 2010
%Y Cf. A020649, A025021, A025022, A025023, A025024, A025025, A025026, A025027, A025028, A025029.
%K nonn,changed
%O 1,1
%A _David W. Wilson_