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 A046002 #28 Feb 16 2025 08:32:38 %S A046002 47,79,103,127,131,179,227,347,443,523,571,619,683,691,739,787,947, %T A046002 1051,1123,1723,1747,1867,2203,2347,2683 %N A046002 Discriminants of imaginary quadratic fields with class number 5 (negated). %H A046002 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 A046002 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 A046002 Keith Matthews, <a href="http://www.numbertheory.org/classnos/">Tables of imaginary quadratic fields with small class numbers</a> %H A046002 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 A046002 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ClassNumber.html">Class Number.</a> %H A046002 <a href="/index/Qua#quadfield">Index entries for sequences related to quadratic fields</a> %t A046002 Union[(-NumberFieldDiscriminant[Sqrt[-#]] &) /@ Select[Range[2700], NumberFieldClassNumber[Sqrt[-#]] == 5 &]] (* _Jean-François Alcover_, Jun 27 2012 *) %o A046002 (PARI) select(n->qfbclassno(-n)==5,vector(670,n,4*n+3)) \\ _Charles R Greathouse IV_, Apr 25 2013 %o A046002 (Sage) [n for n in (1..3000) if is_fundamental_discriminant(-n) and QuadraticField(-n, 'a').class_number()==5] # _G. C. Greubel_, Mar 01 2019 %Y A046002 Cf. A006203, A013658, A014602, A014603, A046003-A046020. %Y A046002 Cf. A191410. %K A046002 nonn,fini,full %O A046002 1,1 %A A046002 _Eric W. Weisstein_