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 A322710 #18 Feb 16 2025 08:33:57 %S A322710 15,20,24,32,35,36,40,48,51,52,60,64,72,75,88,91,99,100,112,115,123, %T A322710 147,148,187,232,235,267,403,427 %N A322710 Negative discriminants with form class number 2 (negated). %C A322710 This is the full sequence. %C A322710 The j-invariants for these discriminants are quadratic integers. See the links below for a full list. %H A322710 Rick L. Shepherd, <a href="http://libres.uncg.edu/ir/uncg/f/Shepherd_uncg_0154M_11099.pdf">Binary quadratic forms and genus theory</a>, Master of Arts Thesis, University of North Carolina at Greensboro, 2013 %H A322710 Jianing Song, <a href="/A322710/a322710.txt">j-invariants for the discriminants with form class number 2 and their Hilbert class polynomials</a> %H A322710 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ClassNumber.html">Class Number</a> %o A322710 (PARI) for(n=1, 500, if((-n)%4<=1&&quadclassunit(-n)[1]==2, print1(n, ", "))) %Y A322710 Cf. A014603, A305474. %Y A322710 Cf. A133675 (negative discriminants with form class group isomorphic to the trivial group), this sequence (isomorphic to C_2), A328825 (isomorphic to C_3), A329182 (isomorphic to C_2 X C_2), A330219 (isomorphic to C_4). %K A322710 nonn,fini,full %O A322710 1,1 %A A322710 _Jianing Song_, Dec 24 2018