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 A038889 #33 Jul 08 2025 22:26:40 %S A038889 2,13,17,19,43,47,53,59,67,83,89,101,103,127,137,149,151,157,179,191, %T A038889 223,229,239,251,257,263,271,281,293,307,331,349,353,359,373,383,389, %U A038889 409,421,433,443,457,461,463,467,491,509,523,557,563,569,577,587,593 %N A038889 Primes p such that 17 is a square mod p. %C A038889 Also primes of the form 2*x^2+x*y-2*y^2 (as well as of the form 2*x^2+5*x*y+y^2). Discriminant = 17. Class = 1. This was originally a separate entry, submitted by Laura Caballero Fernandez, Lourdes Calvo Moguer, Maria Josefa Cano Marquez, Oscar Jesus Falcon Ganfornina and Sergio Garrido Morales (oscfalgan(AT)yahoo.es), Jun 06 2008. _R. J. Mathar_ proved that this coincides with the present sequence, Jul 22 2008 %C A038889 Also, primes which are a square (mod 17) (or, (mod 34), cf. A191025). - _M. F. Hasler_, Jan 15 2016 %D A038889 Z. I. Borevich and I. R. Shafarevich, Number Theory. %H A038889 Vincenzo Librandi, <a href="/A038889/b038889.txt">Table of n, a(n) for n = 1..1000</a> %H A038889 N. J. A. Sloane et al., <a href="https://oeis.org/wiki/Binary_Quadratic_Forms_and_OEIS">Binary Quadratic Forms and OEIS</a> (Index to related sequences, programs, references) %H A038889 D. B. Zagier, <a href="https://doi.org/10.1007/978-3-642-61829-1">Zetafunktionen und quadratische Körper</a>, Springer, 1981. %t A038889 Select[Prime[Range[200]],JacobiSymbol[17,#]!=-1&] (* _Harvey P. Dale_, Sep 20 2011 *) %o A038889 (PARI) is(n)=isprime(n)&&issquare(Mod(17,n)) \\ _Charles R Greathouse IV_, Mar 21 2013 %Y A038889 Cf. A038889 (17 is a square mod p); A141111, A141112 (d=65). %Y A038889 Primes in A035258. %K A038889 nonn %O A038889 1,1 %A A038889 _N. J. A. Sloane_ %E A038889 Edited by _N. J. A. Sloane_, Jul 28 2008 at the suggestion of _R. J. Mathar_