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A112304 Least number whose least prime quadratic nonresidue is prime(n). 0
2, 7, 19, 46, 214, 394, 1114, 3994, 3826, 13666, 83554, 22234, 189814, 644869, 1387786, 1427911, 4355311, 5715319, 12807391, 43030381, 64320754, 133826599, 452980999 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

COMMENTS

In terms of the Legendre symbol (a|p), this sequence can be described as the least number k such that (k|prime(n))=-1 and (k|prime(i))=1 for i=2,..,n-1. Note that a(n) <= A096636(n).

LINKS

Table of n, a(n) for n=2..24.

MATHEMATICA

nn=23; a=Table[0, {nn}]; n=0; done=False; While[ !done, n++; i=2; While[i<nn+2 && JacobiSymbol[n, Prime[i]]==1, i++ ]; If[i>=2 && i<=nn+2 && JacobiSymbol[n, Prime[i]]==-1 && a[[i-1]]==0, a[[i-1]]=n; done=(Times@@a>0)]]; a

CROSSREFS

Cf. A096636 (Smallest prime whose least prime quadratic non-residue is prime(n).).

Sequence in context: A078842 A110299 A209400 * A006589 A238914 A227946

Adjacent sequences:  A112301 A112302 A112303 * A112305 A112306 A112307

KEYWORD

nonn

AUTHOR

T. D. Noe, Sep 02 2005

STATUS

approved

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Last modified May 31 00:53 EDT 2020. Contains 334747 sequences. (Running on oeis4.)