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Primes p with legendre(3,p) = -1.
5

%I #16 Jan 24 2023 12:34:23

%S 2,5,7,17,19,29,31,41,43,53,67,79,89,101,103,113,127,137,139,149,151,

%T 163,173,197,199,211,223,233,257,269,271,281,283,293,307,317,331,353,

%U 367,379,389,401,439,449,461,463,487,499,509,521,523,547,557,569,571,593

%N Primes p with legendre(3,p) = -1.

%C Apart from the first term, primes p such that 3 is not a square mod p.

%C Apart from the first term, identical to A003630.

%H Vincenzo Librandi, <a href="/A038875/b038875.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[Prime@Range[120], JacobiSymbol[3, #] == -1 &] (* _Vincenzo Librandi_, Sep 09 2012 *)

%o (PARI) isok(p) = isprime(p) && (kronecker(3, p) == -1); \\ _Michel Marcus_, Jan 24 2023

%Y Cf. A040117, A003630.

%K nonn

%O 1,1

%A _N. J. A. Sloane_.

%E Edited by _D. S. McNeil_, _R. J. Mathar_ and _N. J. A. Sloane_, Aug 15 2010