A038898 Primes p such that 23 is not a square mod p.

3, 5, 17, 31, 37, 47, 53, 59, 61, 71, 89, 97, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 179, 181, 211, 223, 229, 239, 241, 271, 281, 293, 307, 311, 313, 331, 337, 347, 373, 389, 401, 421, 433, 439

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn

Comments

Inert rational primes in the field Q(sqrt(23)). - N. J. A. Sloane, Dec 26 2017

Also, only entries p == 1 (mod 4) of the sequence are not squares mod 23 (from the quadratic reciprocity law). - Lekraj Beedassy, Jul 21 2004

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000
• Index to sequences related to decomposition of primes in quadratic fields

Programs

Mathematica

Select[Prime@Range[120], JacobiSymbol[23, #] == -1 &] (* Vincenzo Librandi, Sep 08 2012 *)

Extensions

Offset changed from 0 to 1 by Vincenzo Librandi, Sep 08 2012