This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A128006 #14 Aug 21 2025 10:03:41 %S A128006 1,5,5,2,17,13,5,13,29,3,37,25,13,10,17,25,15,53,65,4,65,41,29,25,17, %T A128006 13,41,73,65,85,5,101,61,41,26,37,85,97,65,109,61,89,325,17,125,29,53, %U A128006 65,6,145,85,61,37,137,25,51,13,85,205,73,173,533,20,34,89,7,197,169,113,85 %N A128006 Numerators of rational-valued radii of circles given by 3 distinct integer points in the euclidean plane. %C A128006 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. They are rendered by the pair of sequences A128006/A128007 in increasing order. %H A128006 <a href="/plot2a?name1=A128006&name2=A128007&tform1=untransformed&tform2=untransformed&shift=0&radiop1=ratio&drawpoints=true">Illustration of A128006/A128007 using Plot 2</a>. %Y A128006 See A128007 for denominators. %Y A128006 Cf. A128008, A128009, A128010, A128011, A192493, A192494. %K A128006 frac,nonn %O A128006 1,2 %A A128006 _Heinrich Ludwig_, Feb 11 2007