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A091910 Number of distinct distances between the intersection points in A091908 measured from the center of the equilateral triangle. 2
1, 3, 4, 10, 11, 21, 20, 36, 36, 55, 56, 78, 79, 103, 103, 136, 135 (list; graph; refs; listen; history; text; internal format)



Mohammad K. Azarian, A Trigonometric Characterization of  Equilateral Triangle, Problem 336, Mathematics and Computer Education, Vol. 31, No. 1, Winter 1997, p. 96.  Solution published in Vol. 32, No. 1, Winter 1998, pp. 84-85.

Mohammad K. Azarian, Equating Distances and Altitude in an Equilateral Triangle, Problem 316, Mathematics and Computer Education, Vol. 28, No. 3, Fall 1994, p. 337.  Solution published in Vol. 29, No. 3, Fall 1995, pp. 324-325.


Table of n, a(n) for n=2..18.

Hugo Pfoertner, Visualization of diagonal intersections in an equilateral triangle.

Hugo Pfoertner, Diagonal intersections in an equilateral triangle. Program and results.


a(2)=1: The 3 line segments intersect each other at the triangle center (r=0).

a(3)=3: There are 3 intersection points at r=0.2, 3 at r=0.25 and 6 at r=0.3779645, i.e. 3 different radii. See pictures given at link.


FORTRAN program given at link.


Cf. A091908, A092098.

Sequence in context: A200816 A327300 A047341 * A131179 A079353 A242654

Adjacent sequences:  A091907 A091908 A091909 * A091911 A091912 A091913




Hugo Pfoertner, Feb 19 2004



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Last modified January 16 03:36 EST 2021. Contains 340195 sequences. (Running on oeis4.)