A332421 The number of regions inside a nonagon formed by the straight line segments mutually connecting all vertices and all points that divide the sides into n equal parts.

154, 2754, 16858, 55098, 142318, 298350, 568162, 975294, 1585666, 2426292, 3588508, 5093604, 7067422, 9523746, 12612214, 16351218, 20924029, 26326026, 32789107, 40289238, 49093282, 59181228, 70852528

Offset: 1

Author

Scott R. Shannon and N. J. A. Sloane, Mar 09 2020

Keywords

• nonn
• more

Comments

The terms are from numeric computation - no formula for a(n) is currently known.

Links

• Scott R. Shannon, Nonagon regions for n = 1.
• Scott R. Shannon, Nonagon regions for n = 2.
• Scott R. Shannon, Nonagon regions for n = 3.
• Scott R. Shannon, Nonagon regions with random distance-based coloring for n = 1.
• Scott R. Shannon, Nonagon regions with random distance-based coloring for n = 2.
• Scott R. Shannon, Nonagon regions with random distance-based coloring for n = 3.
• Wikipedia, Nonagon.

Crossrefs

Cf. A332427 (n-gons), A332428 (vertices), A332429 (edges), A007678, A092867, A331452, A331929.

Extensions

a(6)-a(23) from Lars Blomberg, May 16 2020