A038906 - OEIS

A038906

Primes p such that 31 is not a square mod p.

7, 13, 17, 19, 29, 37, 47, 53, 59, 61, 67, 71, 73, 89, 103, 107, 131, 137, 163, 181, 191, 197, 211, 227, 229, 241, 269, 277, 283, 307, 311, 313, 337, 353, 359, 379, 389, 401, 409, 419, 431, 433, 439, 443, 449, 457

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OFFSET

1,1

COMMENTS

Also, only entries p=1 (mod 4) of the sequence are not squares mod 31 (from the quadratic reciprocity law). - Lekraj Beedassy, Jul 21 2004

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[Prime@Range[120], JacobiSymbol[31, #] == -1 &] (* Vincenzo Librandi, Sep 09 2012 *)

CROSSREFS

Sequence in context: A079695 A079698 A237609 * A097959 A156543 A090863

Adjacent sequences: A038903 A038904 A038905 * A038907 A038908 A038909

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

EXTENSIONS

Offset changed from 0 to 1 by Vincenzo Librandi, Sep 09 2012

STATUS

approved