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%I #15 Oct 31 2020 04:35:20
%S 10559,15791,21118,31582,50951,53231,53881,88079,88919,92569,97919,
%T 101902,102001,106462,107762,123191,128519,130729,138311,142271,
%U 144169,158759,166319,166609,167879,173209,174599,176158,176401,177838,185138
%N Numbers whose least quadratic nonresidue (A020649) is 23.
%H Amiram Eldar, <a href="/A025028/b025028.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>.
%o (PARI) residue(n,m)=local(r);r=0;for(i=1,floor(m/2),if(i^2%m==n,r=1));r
%o isA025028(n)=local(a);a=1;forprime(p=2,19,a=a && residue(p,n));a=a && !residue(23,n);a \\ _Michael B. Porter_, Apr 30 2010
%o (PARI) is(n)=forprime(p=2,23, if(!issquare(Mod(p,n)), return(p==23))); 0 \\ _Charles R Greathouse IV_, Jan 24 2020
%Y Cf. A020649, A025020, A025021, A025022, A025023, A025024, A025025, A025026, A025027, A025029.
%K nonn
%O 1,1
%A _David W. Wilson_
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