login
Primes p such that 78 is not a square mod p.
1

%I #9 Sep 08 2022 08:44:53

%S 5,17,19,47,61,67,71,73,79,97,103,107,113,127,131,149,157,163,167,179,

%T 181,193,197,199,233,239,241,251,257,277,293,307,317,331,347,359,367,

%U 373,379,383,409,419,431,439,443

%N Primes p such that 78 is not a square mod p.

%H Vincenzo Librandi, <a href="/A038964/b038964.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[Prime@Range[120], JacobiSymbol[78, #] == - 1 &] (* _Vincenzo Librandi_, Sep 09 2012 *)

%o (Magma) [ p: p in PrimesUpTo(443) | not IsSquare(R! 78) where R:= ResidueClassRing(p) ]; // _Vincenzo Librandi_, Sep 10 2012

%K nonn,easy

%O 1,1

%A _N. J. A. Sloane_.

%E Offset changed from 0 to 1 by _Vincenzo Librandi_, Sep 09 2012