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A128006 Numerators of rational-valued radii of circles given by 3 distinct integer points in the euclidean plane. 8
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, 13, 41, 73, 65, 85, 5, 101, 61, 41, 26, 37, 85, 97, 65, 109, 61, 89, 325, 17, 125, 29, 53, 65, 6, 145, 85, 61, 37, 137, 25, 51, 13, 85, 205, 73, 173, 533, 20, 34, 89, 7, 197, 169, 113, 85 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

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.

LINKS

Table of n, a(n) for n=1..70.

CROSSREFS

See A128007 for denominators.

Cf. A128008, A128009, A128010, A128011, A192493, A192494.

Sequence in context: A023580 A021648 A287746 * A157703 A332507 A242617

Adjacent sequences:  A128003 A128004 A128005 * A128007 A128008 A128009

KEYWORD

frac,nonn

AUTHOR

Heinrich Ludwig, Feb 11 2007

STATUS

approved

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Last modified July 4 14:29 EDT 2020. Contains 335448 sequences. (Running on oeis4.)