This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A333139 #17 May 18 2020 06:19:10 %S A333139 220,4220,25220,84280,217800,456640,873090,1501520,2436020,3736540, %T A333139 5523970,7830800,10879460,14665340,19398660,25173960,32203320, %U A333139 40502280,50458120,61995140,75517160 %N A333139 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 A333139 The terms are from numeric computation - no formula for a(n) is currently known. %H A333139 Scott R. Shannon, <a href="/A333139/a333139.png">Decagon regions for n = 1</a>. %H A333139 Scott R. Shannon, <a href="/A333139/a333139_1.png">Decagon regions for n = 2</a>. %H A333139 Scott R. Shannon, <a href="/A333139/a333139_2.png">Decagon regions for n = 3</a>. %H A333139 Scott R. Shannon, <a href="/A333139/a333139_3.png">Decagon regions with random distance-based coloring for n = 1</a>. %H A333139 Scott R. Shannon, <a href="/A333139/a333139_4.png">Decagon regions with random distance-based coloring for n = 2</a>. %H A333139 Scott R. Shannon, <a href="/A333139/a333139_5.png">Decagon regions with random distance-based coloring for n = 3</a>. %H A333139 Wikipedia, <a href="https://en.wikipedia.org/wiki/Decagon">Decagon</a>. %Y A333139 Cf. A332417 (n-gons), A332418 (vertices), A332419 (edges), A007678, A092867, A331452, A331929. %K A333139 nonn,more %O A333139 1,1 %A A333139 _Scott R. Shannon_ and _N. J. A. Sloane_, Mar 09 2020 %E A333139 a(6)-a(21) from _Lars Blomberg_, May 18 2020