

A067151


Number of regions in regular ngon which are quadrilaterals (4gons).


11



0, 0, 6, 7, 24, 36, 90, 132, 168, 234, 378, 600, 672, 901, 954, 1444, 1580, 2520, 2860, 2990, 3696, 4800, 5070, 6750, 7644, 9309, 7920, 12927, 12896, 15576, 16898, 20475, 18684, 25382, 27246, 30966, 32760, 37064, 37170, 45838, 47300, 55350, 60996
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OFFSET

4,3


REFERENCES

B. Poonen and M. Rubinstein, Number of Intersection Points Made by the Diagonals of a Regular Polygon, SIAM J. Discrete Mathematics, Vol. 11, pp. 135156.


LINKS

Table of n, a(n) for n=4..46.
Sascha Kurz, mgons in regular ngons
B. Poonen and M. Rubinstein, The number of intersection points made by the diagonals of a regular polygon, arXiv version, which has fewer typos than the SIAM version.
B. Poonen and M. Rubinstein, Mathematica programs for these sequences
Sequences formed by drawing all diagonals in regular polygon


EXAMPLE

a(6)=6 because the 6 regions around the center are quadrilaterals.


CROSSREFS

Cf. A007678, A067163, A064869, A067152, A067153, A067154, A067155, A067156, A067157, A067158, A067159.
Sequence in context: A282370 A282005 A282659 * A219916 A135987 A259088
Adjacent sequences: A067148 A067149 A067150 * A067152 A067153 A067154


KEYWORD

easy,nonn


AUTHOR

Sascha Kurz, Jan 06 2002


STATUS

approved



