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 A141778 #35 Mar 17 2025 14:53:44 %S A141778 2,5,11,17,47,53,67,71,73,79,89,97,107,109,131,139,157,167,173,179, %T A141778 199,223,227,233,251,257,263,269,271,277,283,307,311,317,331,347,367, %U A141778 373,401,409,443,449,461,463,467,479,487,509,523,587,601,607,613,619,631 %N A141778 Primes of the form 4*x^2 + 3*x*y - 5*y^2 (as well as of the form 8*x^2 + 11*x*y + y^2). %C A141778 Discriminant = 89. Class = 1. 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 A141778 A subsequence of (and may possibly coincide with) A038977. - _R. J. Mathar_, Jul 22 2008 %D A141778 Z. I. Borevich and I. R. Shafarevich, Number Theory. %H A141778 N. J. A. Sloane et al., <a href="/wiki/Binary_Quadratic_Forms_and_OEIS">Binary Quadratic Forms and OEIS</a>: Index to related sequences, programs, references. OEIS wiki, June 2014. %H A141778 D. B. Zagier, <a href="https://doi.org/10.1007/978-3-642-61829-1">Zetafunktionen und quadratische Körper</a>, Springer, 1981. %e A141778 a(1) = 2 because we can write 2 = 4*1^2 + 3*1*1 - 5*1^2. %Y A141778 See also A038872 (d=5). A038873 (d=8). A068228, A141123 (d=12). A038883 (d=13). A038889 (d=17). A141158 (d=20). A141159, A141160 (d=21). A141170, A141171 (d=24). A141172, A141173 (d=28). A141174, A141175 (d=32). A141176, A141177 (d=33). A141178 (d=37). A141179, A141180 (d=40). A141181 (d=41). A141182, A141183 (d=44). A033212, A141785 (d=45). A068228, A141187 (d=48). A141188 (d=52). A141189 (d=53). A141190, A141191 (d=56). A141192, A141193 (d=57). A107152, A141302, A141303, A141304 (d=60). A141215 (d=61). A141111, A141112 (d=65). A141750 (d=73). A141772, A141773 (d=85). A141776, A141777 (d=88). A141778 (d=89). A141161, A141163 (d=148). A141165, A141166 (d=229). A141167, A141168 (d=257). %K A141778 nonn %O A141778 1,1 %A A141778 Laura Caballero Fernandez, Lourdes Calvo Moguer, Maria Josefa Cano Marquez, Oscar Jesus Falcon Ganfornina and Sergio Garrido Morales (sergarmor(AT)yahoo.es), Jul 04 2008 %E A141778 Typo in crossrefs fixed by _Colin Barker_, Apr 05 2015