A067156 Number of regions in regular n-gon which are 9-gons.

1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 35, 0, 0, 0, 0, 0, 123, 0, 0, 88, 45, 0, 0, 0, 0, 0, 51, 0, 0, 0, 165, 0, 114, 0, 118, 120, 61, 124, 0, 192, 195, 66, 67, 272, 138, 0, 568, 360, 146, 222, 600, 0, 231, 156, 237, 800, 567, 410, 664, 84, 255, 344, 174

Offset

9,27

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. 135-156.

Links

Scott R. Shannon, Table of n, a(n) for n = 9..765

Sascha Kurz, m-gons in regular n-gons

B. Poonen and M. Rubinstein, The number of intersection points made by the diagonals of a regular polygon, SIAM J. on Discrete Mathematics, Vol. 11, No. 1, 135-156 (1998).

Sequences formed by drawing all diagonals in regular polygon

Example

a(9)=1 because drawing the regular 9-gon with all its diagonals yields 1 9-gon.

Crossrefs

Cf. A007678, A067168, A064869, A067151, A067152, A067153, A067154, A067155, A067157, A067158, A067159.

Sequence in context: A189253 A250488 A236237 * A365894 A291452 A343981

Adjacent sequences: A067153 A067154 A067155 * A067157 A067158 A067159

Keyword

nonn

Author

Sascha Kurz, Jan 06 2002

Extensions

a(86) and beyond by Scott R. Shannon, Dec 04 2021

Status

approved