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%I A106753 #3 Oct 12 2012 14:39:32
%S A106753 3,7,8,11,12,15,19,20,23,24,27,28,31,32,35,39,40,43,44,47,48,51,52,55,
%T A106753 56,59,60,63,67,68,71,72,75,76,79,80,83,84,87,88,91,92,95,96,99,103,
%U A106753 104,107,108,111,112,115,116,119,120,123,124,127,128,131,132,135,136,139
%N A106753 Discriminants, negated, of definite binary quadratic forms.
%C A106753 A definite binary quadratic form a*x^2 + b*x*y + c*y^2 over the integers has discriminant D = b^2 - 4*a*c < 0; -D is assumed to be a nonsquare.
%F A106753 -a(n) is 0 (mod 4) or 1 (mod 4), but not a square.
%t A106753 Select[ Range[148], (Mod[ -#, 4] == 0 || Mod[ -#, 4] == 1) && !IntegerQ[Sqrt[ # ]] & ]
%Y A106753 Cf. A014601, A042948 (with squares), A079896 (indefinite case).
%K A106753 easy,nonn
%O A106753 1,1
%A A106753 _Steven Finch_, May 16 2005

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