%I A128007
%S A128007 1,4,3,1,8,6,2,5,10,1,12,8,4,3,5,7,4,14,17,1,16,10,7,6,4,3,9,16,14,18,
               1,
%T A128007 20,12,8,5,7,16,18,12,20,11,16,58,3,22,5,9,11,1,24,14,10,6,22,4,8,2,13,
%U A128007 31,11,26,80,3,5,13,1,28,24,16,12,26,22,7,9,4
%N A128007 Denominators of rational-valued radii of circles given by 3 distinct 
               integer points in the euclidean plane.
%C A128007 A triangle in the euclidean plane defines a circumcircle. There exist 
               only certain rational-valued circumradii if the vertices of the triangle 
               have integer coordinates. The circumradii are rendered by the pair 
               of sequences A128006/A128007 in increasing order.
%Y A128007 See A128006 for numerators. Cf. A128008, A128009, A128010, A128011.
%Y A128007 Sequence in context: A127673 A016698 A038763 this_sequence A098458 A165914 
               A139621
%Y A128007 Adjacent sequences: A128004 A128005 A128006 this_sequence A128008 A128009 
               A128010
%K A128007 frac,nonn
%O A128007 1,2
%A A128007 Heinrich Ludwig (lud.wig(AT)t-online.de), Feb 11 2007