The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A217753 Number of noncongruent polygonal regions with finite area in the exterior of a regular n-gon with all diagonals drawn. 1
 0, 0, 0, 0, 1, 2, 5, 7, 14, 18, 30, 35, 55, 62, 90 (list; graph; refs; listen; history; text; internal format)
 OFFSET 3,6 LINKS EXAMPLE a(7) = 1 since the 35 exterior regions of the regular heptagon built by all diagonals consist of one noncongruent polygon, i.e., 1 triangle (7 times), and three different noncongruent regions with infinite area (two 7 times, one 14 times). a(8) = 2 since the 64 exterior regions of the regular octagon built by all diagonals consist of two different noncongruent polygons, i.e., 2 triangles (one 8 times, one 16 times), and three different noncongruent regions with infinite area (one 8 times, two 16 times). a(9) = 5 since the 117 exterior regions of the regular 9-gon (nonagon) built by all diagonals consist of five different noncongruent polygons, i.e., 3 triangles (one 9 times, two 18 times) and 2 quadrilaterals (each 9 times), and four different noncongruent regions with infinite area (two 9 times, two 18 times). CROSSREFS Cf. A004526, A187781, A217745, A217746, A217748, A217754. Sequence in context: A044990 A266259 A133146 * A022771 A132603 A022765 Adjacent sequences:  A217750 A217751 A217752 * A217754 A217755 A217756 KEYWORD nonn AUTHOR Martin Renner, Mar 23 2013 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified April 9 10:32 EDT 2020. Contains 333348 sequences. (Running on oeis4.)