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%I A046003 #39 Mar 01 2019 16:28:55
%S A046003 87,104,116,152,212,244,247,339,411,424,436,451,472,515,628,707,771,
%T A046003 808,835,843,856,1048,1059,1099,1108,1147,1192,1203,1219,1267,1315,
%U A046003 1347,1363,1432,1563,1588,1603,1843,1915,1963,2227,2283,2443,2515,2563,2787,2923,3235,3427,3523,3763
%N A046003 Discriminants of imaginary quadratic fields with class number 6 (negated).
%H A046003 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 A046003 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 A046003 Keith Matthews, <a href="http://www.numbertheory.org/classnos/">Tables of imaginary quadratic fields with small class numbers</a>.
%H A046003 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 A046003 Mark Watkins, <a href="https://doi.org/10.1090/S0025-5718-03-01517-5">Class numbers of imaginary quadratic fields</a>, Mathematics of Computation, 73, pp. 907-938
%H A046003 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/ClassNumber.html">Class Number.</a>
%H A046003 <a href="/index/Qua#quadfield">Index entries for sequences related to quadratic fields</a>
%t A046003 Union[(-NumberFieldDiscriminant[Sqrt[-#]] &) /@ Select[Range[3800], NumberFieldClassNumber[Sqrt[-#]] == 6 &]] (* _Jean-François Alcover_, Jun 27 2012 *)
%o A046003 (PARI) ok(n)={isfundamental(-n) && quadclassunit(-n).no == 6};
%o A046003 for(n=1, 4000, if(ok(n)==1, print1(n, ", "))) \\ _G. C. Greubel_, Mar 01 2019
%o A046003 (Sage) [n for n in (1..4000) if is_fundamental_discriminant(-n) and QuadraticField(-n, 'a').class_number()==6] # _G. C. Greubel_, Mar 01 2019
%Y A046003 Cf. A006203, A013658, A014602, A014603, A046002-A046020.
%Y A046003 Cf. A191410.
%K A046003 nonn,fini,full
%O A046003 1,1
%A A046003 _Eric W. Weisstein_
%E A046003 More terms from _Seiichi Manyama_, Jun 03 2018

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