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Primes that are not in A038881.
5

%I #33 Jul 04 2023 10:11:28

%S 2,3,13,17,23,29,31,41,47,59,61,67,71,73,101,103,109,149,163,173,179,

%T 191,193,197,199,223,233,241,251,277,281,293,311,331,337,349,367,373,

%U 379,383,409,419,443,457,461,463

%N Primes that are not in A038881.

%C Also, only entries p == 1 (mod 4) of the sequence are not squares mod 11 (from the quadratic reciprocity law). - _Lekraj Beedassy_, Jul 21 2004

%C Except for 2, inert primes in Z[sqrt(11)]. 2 splits as (-1)*(3 - sqrt(11))*(3 + sqrt(11)). Cf. A296936. - _Alonso del Arte_, Jan 02 2015

%H Vincenzo Librandi, <a href="/A038882/b038882.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[Prime@Range[120], JacobiSymbol[11, #] == -1 &] (* _Vincenzo Librandi_, Sep 08 2012 *)

%o (PARI) isok(p) = isprime(p) && !((p%2) && issquare(Mod(11, p))); \\ _Michel Marcus_, Jul 04 2023

%Y Cf. A019339, A038881, A296936.

%K nonn

%O 1,1

%A _N. J. A. Sloane_

%E Offset changed from 0 to 1 by _Vincenzo Librandi_, Sep 08 2012

%E Definition edited by _N. J. A. Sloane_, Jul 04 2023