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

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn

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

Programs

Mathematica

Select[Prime[Range[100]], JacobiSymbol[31, #] != -1 &] (* Vincenzo Librandi, Sep 07 2012 *)