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 A141303 #27 May 26 2024 13:56:59 %S A141303 2,5,17,53,113,137,173,197,233,257,293,317,353,557,593,617,653,677, %T A141303 773,797,857,953,977,1013,1097,1193,1217,1277,1373,1433,1493,1553, %U A141303 1613,1637,1697,1733,1877,1913,1973,1997,2153,2213,2237,2273,2297,2333,2357,2393,2417,2477 %N A141303 Primes of the form 2*x^2+6*x*y-3*y^2 (as well as of the form 5*x^2+10*x*y+2*y^2). %C A141303 Discriminant = 60. Class = 4. Binary quadratic forms a*x^2+b*x*y+c*y^2 have discriminant d=b^2-4ac and gcd(a,b,c)=1. %C A141303 This is also the list of primes p such that p = 2 or 5 or p is congruent to 17 or 53 mod 60. - _Jean-François Alcover_, Oct 28 2016 %D A141303 Z. I. Borevich and I. R. Shafarevich, Number Theory. %H A141303 Juan Arias-de-Reyna, <a href="/A141303/b141303.txt">Table of n, a(n) for n = 1..10000</a> %H A141303 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. OEIS wiki, June 2014. %H A141303 D. B. Zagier, <a href="https://doi.org/10.1007/978-3-642-61829-1">Zetafunktionen und quadratische Körper</a>, Springer, 1981. %e A141303 a(3)=17 because we can write 17=2*2^2+6*2*1-3*1^2 (or 17=5*1^2+10*1*1+2*1^2). %t A141303 Select[Prime[Range[500]], # == 2 || # == 5 || MatchQ[Mod[#, 60], 17|53]&] (* _Jean-François Alcover_, Oct 28 2016 *) %Y A141303 Cf. A107152, A141302, A141304 (d=60), A107167. %Y A141303 Primes in A243189. %K A141303 nonn %O A141303 1,1 %A A141303 Laura Caballero Fernandez, Lourdes Calvo Moguer, Maria Josefa Cano Marquez, Oscar Jesus Falcon Ganfornina and Sergio Garrido Morales (oscfalgan(AT)yahoo.es), Jun 24 2008