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 A046016 #21 Feb 16 2025 08:32:38 %S A046016 311,359,919,1063,1543,1831,2099,2339,2459,3343,3463,3467,3607,4019, %T A046016 4139,4327,5059,5147,5527,5659,6803,8419,8923,8971,9619,10891,11299, %U A046016 15091,15331,16363,16747,17011,17299,17539,17683,19507,21187,21211,21283,23203,24763,26227,27043,29803,31123,37507,38707 %N A046016 Discriminants of imaginary quadratic fields with class number 19 (negated). %C A046016 47 discriminants in this sequence (proved). %H A046016 Steven Arno, M. L. Robinson, Ferrell S. Wheeler, <a href="http://matwbn.icm.edu.pl/ksiazki/aa/aa83/aa8341.pdf">Imaginary quadratic fields with small odd class number</a>, Acta Arith. 83 (1998) 295-330. %H A046016 Duncan A. Buell, <a href="https://dx.doi.org/10.1090/S0025-5718-1977-0439802-X">Small class numbers and extreme values of L-functions of quadratic fields</a>, Math. Comp., 31 (1977), 786-796. %H A046016 Keith Matthews, <a href="http://www.numbertheory.org/classnos/">Tables of imaginary quadratic fields with small class numbers</a> %H A046016 C. Wagner, <a href="https://dx.doi.org/10.1090/S0025-5718-96-00722-3">Class Number 5, 6 and 7</a>, Math. Comput. 65, 785-800, 1996. %H A046016 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ClassNumber.html">Class Number.</a> %H A046016 <a href="/index/Qua#quadfield">Index entries for sequences related to quadratic fields</a> %t A046016 Reap[ For[ n = 1, n < 40000, n++, s = Sqrt[-n]; If[ NumberFieldClassNumber[s] == 19, d = -NumberFieldDiscriminant[s]; Print[d]; Sow[d]]]][[2, 1]] // Union (* _Jean-François Alcover_, Oct 05 2012 *) %Y A046016 Cf. A006203, A013658, A014602, A014603, A046002-A046020. %K A046016 nonn,fini,full %O A046016 1,1 %A A046016 _Eric W. Weisstein_