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A217745 Number of regions in the exterior of a regular n-gon with all diagonals drawn. 3
1, 4, 10, 18, 35, 64, 117, 190, 330, 492, 780, 1050, 1605, 2080, 2941 (list; graph; refs; listen; history; text; internal format)
OFFSET
3,2
LINKS
EXAMPLE
a(3) = 1 since the equilateral triangle has no diagonals and therefore one exterior region (with infinite area).
a(4) = 4 since the two diagonals of the square divide the exterior in four regions (with infinite area).
a(5) = 10 since the ten diagonals of the regular pentagon divide the exterior in ten regions (with infinite area) of two different shapes.
CROSSREFS
Cf. A007678.
Sequence in context: A050188 A062361 A038416 * A213949 A009913 A063591
KEYWORD
nonn
AUTHOR
Martin Renner, Mar 23 2013
STATUS
approved

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Last modified April 18 22:18 EDT 2024. Contains 371782 sequences. (Running on oeis4.)