%I #26 May 25 2024 14:36:22
%S 14,17,21,30,33,34,39,42,46,55,57,70,73,78,82,85,93,97,102,130,133,
%T 142,155,177,190,193,195,203,219,253,259,291,323,355,435,483,555,595,
%U 627,667,715,723,763,795,955,1003,1027,1227,1243,1387,1411,1435,1507,1555
%N Numbers n such that Q(sqrt(-n)) has class number 4.
%C Contains 54 numbers [Arno, Theorem 7], ..., 1387, 1411, 1435, 1507 and 1555. [_R. J. Mathar_, May 01 2010]
%H Steven Arno, <a href="http://matwbn.icm.edu.pl/ksiazki/aa/aa60/aa6042.pdf">The imaginary quadratic fields of class number 4</a>, Acta Arithm. vol 60 issue 4 (1991).
%H 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 Keith Matthews, <a href="http://www.numbertheory.org/classnos/">Tables of imaginary quadratic fields with small class numbers</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/PythagoreanTriple.html">Pythagorean Triple.</a>
%H <a href="/index/Qua#quadfield">Index entries for sequences related to quadratic fields</a>
%o (PARI) \\ See A005847
%Y See A003173, A005847, A006203, A046085, A046002, A055109, A046004, A055110, A046006, A055111 for class numbers 1 through 10.
%K nonn,fini,full
%O 1,1
%A _N. J. A. Sloane_, Jun 16 2000