A112304 Least number whose least prime quadratic nonresidue is prime(n).

2, 7, 19, 46, 214, 394, 1114, 3994, 3826, 13666, 83554, 22234, 189814, 644869, 1387786, 1427911, 4355311, 5715319, 12807391, 43030381, 64320754, 133826599, 452980999

Offset: 2

Author

T. D. Noe, Sep 02 2005

Keywords

• nonn

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).

Crossrefs

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

Programs

Mathematica

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