%I #20 Dec 04 2021 12:26:14
%S 0,0,0,9,0,22,0,39,0,105,48,136,18,190,120,462,66,644,72,875,390,1296,
%T 952,1595,450,1891,1472,3201,2346,3640,2124,4773,2698,5577,4000,7298,
%U 3444,7912,6336,10980,6532,10904,7824,14651,12150,16779,13260,20299,13176,21560,18200,26961,21634,29500
%N Number of regions in regular n-gon which are hexagons.
%D B. Poonen and M. Rubinstein, Number of Intersection Points Made by the Diagonals of a Regular Polygon, SIAM J. Discrete Mathematics, Vol. 11, pp. 135-156.
%H Scott R. Shannon, <a href="/A067153/b067153.txt">Table of n, a(n) for n = 6..765</a>
%H Sascha Kurz, <a href="http://www.mathe2.uni-bayreuth.de/sascha/oeis/drawing/drawing.html">m-gons in regular n-gons</a>
%H B. Poonen and M. Rubinstein, <a href="http://math.mit.edu/~poonen/">The number of intersection points made by the diagonals of a regular polygon</a>, SIAM J. on Discrete Mathematics, Vol. 11, No. 1, 135-156 (1998).
%H <a href="/index/Pol#Poonen">Sequences formed by drawing all diagonals in regular polygon</a>
%e a(9)=9 because drawing the regular 9-gon with all its diagonals yields 9 hexagons.
%Y Cf. A007678, A067165, A064869, A067151, A067152, A067154, A067155, A067156, A067157, A067158, A067159.
%K nonn
%O 6,4
%A _Sascha Kurz_, Jan 06 2002
%E a(54) and beyond by _Scott R. Shannon_, Dec 04 2021