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A331929 The number of regions inside a pentagon formed by the straight line segments mutually connecting all vertices and all points that divide the sides into n equal parts.

%I A331929 #21 May 11 2020 09:44:57
%S A331929 11,170,1161,3900,10741,22380,44491,76610,126336,194070,290651,410860,
%T A331929 577721,779340,1035676,1345030,1730696,2176040,2724036,3345880,
%U A331929 4087656,4933200,5921991,7018210,8300896,9723300,11339151,13122120,15150271,17345140,19843056
%N A331929 The number of regions inside a pentagon formed by the straight line segments mutually connecting all vertices and all points that divide the sides into n equal parts.
%C A331929 The terms are from numeric computation - no formula for a(n) is currently known.
%H A331929 Lars Blomberg, <a href="/A331929/b331929.txt">Table of n, a(n) for n = 1..35</a>
%H A331929 Scott R. Shannon, <a href="/A331929/a331929.png">Pentagon regions for n = 1</a>.
%H A331929 Scott R. Shannon, <a href="/A331929/a331929_1.png">Pentagon regions for n = 2</a>.
%H A331929 Scott R. Shannon, <a href="/A331929/a331929_2.png">Pentagon regions for n = 3</a>.
%H A331929 Scott R. Shannon, <a href="/A331929/a331929_3.png">Pentagon regions for n = 4</a>.
%H A331929 Scott R. Shannon, <a href="/A331929/a331929_4.png">Pentagon regions for n = 5</a>.
%H A331929 Scott R. Shannon, <a href="/A331929/a331929_5.png">Pentagon regions for n = 6</a>.
%H A331929 Scott R. Shannon, <a href="/A331929/a331929_6.png">Pentagon regions for n = 7</a>.
%H A331929 Scott R. Shannon, <a href="/A331929/a331929_7.png">Pentagon regions for n = 8</a>.
%H A331929 Scott R. Shannon, <a href="/A331929/a331929_8.png">Pentagon regions for n = 5, random distance-based coloring</a>.
%H A331929 Scott R. Shannon, <a href="/A331929/a331929_9.png">Pentagon regions for n = 6, random distance-based coloring</a>
%H A331929 Wikipedia, <a href="https://en.wikipedia.org/wiki/Pentagon">Pentagon</a>.
%Y A331929 Cf. A331939 (n-gons), A329710 (edges), A330847 (vertices), A007678, A092867, A331452, A331931.
%K A331929 nonn
%O A331929 1,1
%A A331929 _Scott R. Shannon_ and _N. J. A. Sloane_, Feb 01 2020
%E A331929 a(9) and beyond from _Lars Blomberg_, May 11 2020