OFFSET
3,7
EXAMPLE
a(7) = 1 since the 35 exterior regions of the regular heptagon built by all diagonals consist of one kind of polygon (with finite area), i.e., 1 triangle (7 times), and three different regions with infinite area (two 7 times, one 14 times).
a(8) = 1 since the 64 exterior regions of the regular octagon built by all diagonals consist of one kind of polygon (with finite area), i.e., 2 triangles (one 8 times, one 16 times), and three different regions with infinite area (one 8 times, two 16 times).
a(9) = 2 since the 117 exterior regions of the regular 9-gon (nonagon) built by all diagonals consist of two different kinds of polygons (with finite area), i.e., 3 triangles (one 9 times, two 18 times) and 2 quadrilaterals (each 9 times), and four different regions with infinite area (two 9 times, two 18 times).
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Martin Renner, Mar 23 2013
STATUS
approved