cp's OEIS Frontend

A340686 The number of vertices on a concave circular triangle formed by the straight line segments mutually connecting all vertices and all points that divide the sides into n equal parts.

%I A340686 #10 Jan 17 2021 11:23:31
%S A340686 3,10,24,76,168,391,819,1447,2949,4153,6393,8293,12048,14857,20670,
%T A340686 25972,33123,41026,50379,63700,76560,96628,113262,135076,160050,
%U A340686 183484,215355,244435,288861,322276,371742,424279,470838,534376,597033,682264,760959,854755,941706,1039255,1141569,1254190
%N A340686 The number of vertices on a concave circular triangle formed by the straight line segments mutually connecting all vertices and all points that divide the sides into n equal parts.
%C A340686 The terms are from numeric computation - no formula for a(n) is currently known.
%H A340686 Scott R. Shannon, <a href="/A340686/a340686.png">Vertices for n = 2</a>.
%H A340686 Scott R. Shannon, <a href="/A340686/a340686_1.png">Vertices for n = 3</a>.
%H A340686 Scott R. Shannon, <a href="/A340686/a340686_2.png">Vertices for n = 4</a>.
%H A340686 Scott R. Shannon, <a href="/A340686/a340686_3.png">Vertices for n = 6</a>.
%H A340686 Scott R. Shannon, <a href="/A340686/a340686_4.png">Vertices for n = 8</a>.
%H A340686 Scott R. Shannon, <a href="/A340686/a340686_5.png">Vertices for n = 10</a>.
%H A340686 Scott R. Shannon, <a href="/A340686/a340686_6.png">Vertices for n = 14</a>.
%H A340686 Scott R. Shannon, <a href="/A340686/a340686_7.png">Vertices for n = 15</a>.
%H A340686 Wikipedia, <a href="https://en.wikipedia.org/wiki/Circular_triangle">Circular triangle</a>.
%Y A340686 Cf. A340685 (regions), A340687 (edges), A340688 (n-gons), A340644, A007678, A092867.
%K A340686 nonn
%O A340686 1,1
%A A340686 _Scott R. Shannon_ and _N. J. A. Sloane_, Jan 16 2021