%I #9 Aug 28 2016 04:12:29

%S 3,2,2,7,5,3,7,2,5,2,3,13,3,5,2,3,2,5,3,7,3,2,5,2,11,7,3,5,7,2,2,3,11,

%T 7,3,5,2,3,2,11,3,5,3,2,5,2,7,7,3,5,5,2,13,2,3,5,3,7,2,3,2,13,3,5,5,3,

%U 2,7,2,5,11,3,5,2,11,2,3,5,5,3,7,2,3,2,7,3,7,5,3,2,2,5,5,3,11,11,2,5,2,3,7

%N Let k = n-th nonsquare = A000037(n); then a(n) = smallest prime p such that the Kronecker-Jacobi symbol K(k,p) = -1.

%C Maple calls K(k,p) the Legendre symbol.

%C The old entry with this sequence number was a duplicate of A024356.

%D H. Cohen, A Course in Computational Number Theory, Springer, 1996 (p. 28 defines the Kronecker-Jacobi symbol).

%H Charles R Greathouse IV, <a href="/A092419/b092419.txt">Table of n, a(n) for n = 1..10000</a>

%p with(numtheory); f:=proc(n) local M,i,j,k; M:=100000; for i from 1 to M do if legendre(n,ithprime(i)) = -1 then RETURN(ithprime(i)); fi; od; -1; end;

%o (PARI) a(n)=my(k=n+(sqrtint(4*n)+1)\2); forprime(p=2,, if(kronecker(k,p)<0, return(p))) \\ _Charles R Greathouse IV_, Aug 28 2016

%Y Cf. A000037. Records: A067073, A070040. See A144294 for another version.

%K nonn

%O 1,1

%A _N. J. A. Sloane_, Oct 16 2008, Oct 17 2008. Definition corrected Dec 03 2008.