%I #17 May 18 2020 06:19:10
%S 220,4220,25220,84280,217800,456640,873090,1501520,2436020,3736540,
%T 5523970,7830800,10879460,14665340,19398660,25173960,32203320,
%U 40502280,50458120,61995140,75517160
%N The number of regions inside a decagon formed by the straight line segments mutually connecting all vertices and all points that divide the sides into n equal parts.
%C The terms are from numeric computation - no formula for a(n) is currently known.
%H Scott R. Shannon, <a href="/A333139/a333139.png">Decagon regions for n = 1</a>.
%H Scott R. Shannon, <a href="/A333139/a333139_1.png">Decagon regions for n = 2</a>.
%H Scott R. Shannon, <a href="/A333139/a333139_2.png">Decagon regions for n = 3</a>.
%H Scott R. Shannon, <a href="/A333139/a333139_3.png">Decagon regions with random distance-based coloring for n = 1</a>.
%H Scott R. Shannon, <a href="/A333139/a333139_4.png">Decagon regions with random distance-based coloring for n = 2</a>.
%H Scott R. Shannon, <a href="/A333139/a333139_5.png">Decagon regions with random distance-based coloring for n = 3</a>.
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Decagon">Decagon</a>.
%Y Cf. A332417 (n-gons), A332418 (vertices), A332419 (edges), A007678, A092867, A331452, A331929.
%K nonn,more
%O 1,1
%A _Scott R. Shannon_ and _N. J. A. Sloane_, Mar 09 2020
%E a(6)-a(21) from _Lars Blomberg_, May 18 2020
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