This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A038875 #18 Jul 08 2025 22:25:33 %S A038875 2,5,7,17,19,29,31,41,43,53,67,79,89,101,103,113,127,137,139,149,151, %T A038875 163,173,197,199,211,223,233,257,269,271,281,283,293,307,317,331,353, %U A038875 367,379,389,401,439,449,461,463,487,499,509,521,523,547,557,569,571,593 %N A038875 Primes p with legendre(3,p) = -1. %C A038875 Apart from the first term, primes p such that 3 is not a square mod p. %C A038875 Apart from the first term, identical to A003630. %H A038875 Vincenzo Librandi, <a href="/A038875/b038875.txt">Table of n, a(n) for n = 1..1000</a> %t A038875 Select[Prime@Range[120], JacobiSymbol[3, #] == -1 &] (* _Vincenzo Librandi_, Sep 09 2012 *) %o A038875 (PARI) isok(p) = isprime(p) && (kronecker(3, p) == -1); \\ _Michel Marcus_, Jan 24 2023 %Y A038875 Cf. A040117, A003630. %K A038875 nonn %O A038875 1,1 %A A038875 _N. J. A. Sloane_ %E A038875 Edited by _D. S. McNeil_, _R. J. Mathar_ and _N. J. A. Sloane_, Aug 15 2010