A337700 - OEIS

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A337700

Place two n-gons with radii 1 and 2 concentrically, forming an annular area between them. Connect all the vertices with line segments that lie entirely within that area. Then a(n) is the number of regions in that figure.

12, 16, 20, 24, 63, 72, 315, 350, 385, 408, 767, 826, 2085, 2224, 2363, 2340, 3762, 3960, 7644, 8008, 8372, 8448, 11850, 12324, 20466, 21224, 21982, 21480, 28985, 29920, 45177, 46546, 47915, 48456, 60273, 61902, 87555, 89800, 92045, 91896, 111972, 114576

(list; graph; refs; listen; history; text; internal format)

OFFSET

3,1

COMMENTS

Because of symmetry, a(n) is divisible by n.

LINKS

Lars Blomberg, Table of n, a(n) for n = 3..102

Lars Blomberg, Illustration for n = 3

Lars Blomberg, Illustration for n = 4

Lars Blomberg, Illustration for n = 5

Lars Blomberg, Illustration for n = 7

Lars Blomberg, Illustration for n = 10