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A128007 Denominators of rational-valued radii of circles given by 3 distinct integer points in the Euclidean plane. 8
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, 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, 31, 11, 26, 80, 3, 5, 13, 1, 28, 24, 16, 12, 26, 22, 7, 9, 4 (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. The circumradii are rendered by the pair of sequences A128006/A128007 in increasing order.

LINKS

Table of n, a(n) for n=1..75.

CROSSREFS

See A128006 for numerators.

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

Sequence in context: A332496 A038763 A200384 * A098458 A165914 A139621

Adjacent sequences:  A128004 A128005 A128006 * A128008 A128009 A128010

KEYWORD

frac,nonn

AUTHOR

Heinrich Ludwig, Feb 11 2007

STATUS

approved

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Last modified July 12 21:31 EDT 2020. Contains 335669 sequences. (Running on oeis4.)