A367663 - OEIS

%I #13 Dec 01 2023 20:43:35

%S 6,13,55,223,673,1753,3787,6937,11851,19297,30211,42877,63247,86323,

%T 114049,155701,204169,251293,329989,400081,487537,607189,742747,

%U 858241,1041835,1231789,1424647,1667659,1968427,2165947,2600779,2939863,3286159,3784153,4217395,4687771,5688804,6316332

%N Number of vertices formed in a hexagon by straight line segments when connecting the n-1 points between each corner that divide each edge into n equal parts to the n-1 points on the edge on the opposite side of the hexagon.

%C Keyword "look" is because of the linked images. - _N. J. A. Sloane_, Dec 01 2023

%H Scott R. Shannon, <a href="/A367663/a367663_2.png">Image for n = 2</a>.

%H Scott R. Shannon, <a href="/A367663/a367663.png">Image for n = 4</a>.

%H Scott R. Shannon, <a href="/A367663/a367663_1.png">Image for n = 6</a>.

%H Scott R. Shannon, <a href="/A367663/a367663_3.png">Image for n = 9</a>.

%F a(n) = A367664(n) - A367662(n) + 1 by Euler's formula.

%Y Cf. A367662 (regions), A367664 (edges), A367665 (k-gons), A355799.

%K nonn,look

%O 1,1

%A _Scott R. Shannon_, Nov 26 2023