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Least number whose least prime quadratic nonresidue is prime(n).
0

%I #4 Mar 30 2012 17:22:41

%S 2,7,19,46,214,394,1114,3994,3826,13666,83554,22234,189814,644869,

%T 1387786,1427911,4355311,5715319,12807391,43030381,64320754,133826599,

%U 452980999

%N Least number whose least prime quadratic nonresidue is prime(n).

%C 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).

%t 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

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

%K nonn

%O 2,1

%A _T. D. Noe_, Sep 02 2005