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A092419
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Let k = n-th nonsquare = A000037(n); then a(n) = smallest prime p such that the Kronecker-Jacobi symbol K(k,p) = -1.
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7
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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, 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, 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
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OFFSET
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1,1
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COMMENTS
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Maple calls K(k,p) the Legendre symbol.
The old entry with this sequence number was a duplicate of A024356.
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REFERENCES
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H. Cohen, A Course in Computational Number Theory, Springer, 1996 (p. 28 defines the Kronecker-Jacobi symbol).
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LINKS
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MAPLE
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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;
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PROG
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(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
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane, Oct 16 2008, Oct 17 2008. Definition corrected Dec 03 2008.
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STATUS
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approved
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