%I A033197
%S A033197 4,8,3,20,24,7,40,11,52,56,15,68,19,84,88,23,104,116,120,31,132,
%T A033197 136,35,148,152,39,164,168,43,184,47,51,212,55,228,232,59,244,248,
%U A033197 260,264,67,276,280,71,292,296,308,312,79,328,83,340,344,87,356
%V A033197 -4,-8,-3,-20,-24,-7,-40,-11,-52,-56,-15,-68,-19,-84,-88,-23,-104,-116,
               -120,-31,-132,
%W A033197 -136,-35,-148,-152,-39,-164,-168,-43,-184,-47,-51,-212,-55,-228,-232,
               -59,-244,-248,
%X A033197 -260,-264,-67,-276,-280,-71,-292,-296,-308,-312,-79,-328,-83,-340,-344,
               -87,-356
%N A033197 Discriminants of quadratic number fields Q(sqrt -n) for n square-free.
%D A033197 D. Cox, "Primes of Form x^2 + n y^2", Wiley, 1989, p. 103.
%H A033197 T. D. Noe, <a href="b033197.txt">Table of n, a(n) for n=1..10000</a>
%F A033197 For n square-free and negative, a(n)=n if n=1 mod 4 else 4n.
%o A033197 (PARI) bnd = 1000; L = vector(bnd); j = 1; for (i=1,bnd, if(issquarefree(i),
               L[j]=i:j=j+1)); M = vector(j-1); for (i=1,j-1,M[i]=if((L[i]%4==3),
               -L[i],-4*L[i])); M
%Y A033197 Values of n run through A005117. See A000924 for class numbers of these 
               fields.
%Y A033197 Sequence in context: A021678 A066199 A103647 this_sequence A124002 A014457 
               A092511
%Y A033197 Adjacent sequences: A033194 A033195 A033196 this_sequence A033198 A033199 
               A033200
%K A033197 sign,easy,nice
%O A033197 1,1
%A A033197 N. J. A. Sloane (njas(AT)research.att.com).