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 A332421 #28 May 16 2020 06:32:12 %S A332421 154,2754,16858,55098,142318,298350,568162,975294,1585666,2426292, %T A332421 3588508,5093604,7067422,9523746,12612214,16351218,20924029,26326026, %U A332421 32789107,40289238,49093282,59181228,70852528 %N 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. %C A332421 The terms are from numeric computation - no formula for a(n) is currently known. %H A332421 Scott R. Shannon, <a href="/A332421/a332421.png">Nonagon regions for n = 1</a>. %H A332421 Scott R. Shannon, <a href="/A332421/a332421_1.png">Nonagon regions for n = 2</a>. %H A332421 Scott R. Shannon, <a href="/A332421/a332421_2.png">Nonagon regions for n = 3</a>. %H A332421 Scott R. Shannon, <a href="/A332421/a332421_3.png">Nonagon regions with random distance-based coloring for n = 1</a>. %H A332421 Scott R. Shannon, <a href="/A332421/a332421_4.png">Nonagon regions with random distance-based coloring for n = 2</a>. %H A332421 Scott R. Shannon, <a href="/A332421/a332421_5.png">Nonagon regions with random distance-based coloring for n = 3</a>. %H A332421 Wikipedia, <a href="https://en.wikipedia.org/wiki/Nonagon">Nonagon</a>. %Y A332421 Cf. A332427 (n-gons), A332428 (vertices), A332429 (edges), A007678, A092867, A331452, A331929. %K A332421 nonn,more %O A332421 1,1 %A A332421 _Scott R. Shannon_ and _N. J. A. Sloane_, Mar 09 2020 %E A332421 a(6)-a(23) from _Lars Blomberg_, May 16 2020