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A128008 Numerators of rational-valued radii of circles given by 3 distinct integer points in the 3-dimensional Euclidean space. 6
1, 5, 3, 5, 11, 2, 17, 13, 9, 7, 33, 5, 13, 21, 27, 17, 29, 3, 37, 25, 19, 13, 33, 10, 17, 41, 7, 25, 29, 51, 11, 15, 53, 19, 99, 65, 23, 27, 4, 65, 57, 49, 41, 33, 29, 25, 21, 59, 17, 43, 69, 13, 53, 31, 9, 41, 73, 83, 37, 65, 14, 33, 85, 105, 43, 67, 77, 29, 63, 69, 89, 5 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A triangle in the 3-dimensional Euclidean space 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 A128008/A128009 in increasing order.

LINKS

Table of n, a(n) for n=1..72.

CROSSREFS

See A128009 for denominators. Cf. A128006, A128007, A128010, A128011.

Sequence in context: A185046 A114740 A330523 * A265800 A144386 A256787

Adjacent sequences:  A128005 A128006 A128007 * A128009 A128010 A128011

KEYWORD

frac,nonn

AUTHOR

Heinrich Ludwig, Feb 14 2007

STATUS

approved

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Last modified June 13 22:55 EDT 2021. Contains 345016 sequences. (Running on oeis4.)