A038905 - OEIS

A038905

31 is a square mod p.

2, 3, 5, 11, 23, 31, 41, 43, 79, 83, 97, 101, 109, 113, 127, 139, 149, 151, 157, 167, 173, 179, 193, 199, 223, 233, 239, 251, 257, 263, 271, 281, 293, 317, 331, 347, 349, 367, 373, 383, 397, 421, 463, 487, 491

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OFFSET

1,1

COMMENTS

Also, only entries p=1 (mod 4) of the sequence are 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[100]], JacobiSymbol[31, #] != -1 &] (* Vincenzo Librandi, Sep 07 2012 *)

CROSSREFS

Sequence in context: A118504 A215714 A350100 * A019405 A079848 A329749

Adjacent sequences: A038902 A038903 A038904 * A038906 A038907 A038908

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

STATUS

approved