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A025028 Least non-residue mod n is 23. 0

%I

%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 Least non-residue mod n is 23.

%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

%K nonn

%O 1,1

%A _David W. Wilson_

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Last modified May 31 12:48 EDT 2020. Contains 334748 sequences. (Running on oeis4.)