cp's OEIS Frontend

A335784 Irregular table read by rows: n-sect the angles of a nonagon (enneagon). Then T(n,k) = number of k-sided polygons in that figure for k >= 3.

%I A335784 #10 Jun 24 2020 10:06:07
%S A335784 0,0,0,0,0,0,1,18,36,81,9,0,0,0,0,0,0,0,0,0,0,0,0,1,126,36,180,135,18,
%T A335784 45,9,0,0,0,0,0,0,0,0,0,0,1,288,126,54,90,36,18,9,0,0,1,450,306,72,18,
%U A335784 576,369,207,126,0,9,0,0,0,0,0,0,0,0,0,1
%N A335784 Irregular table read by rows: n-sect the angles of a nonagon (enneagon). Then T(n,k) = number of k-sided polygons in that figure for k >= 3.
%C A335784 For n<=200 no polygon has more than 18 edges.
%C A335784 See A335781 for illustrations.
%H A335784 Lars Blomberg, <a href="/A335784/b335784.txt">Table of n, a(n) for n = 1..2217</a> (the first 200 rows)
%e A335784 The table begins:
%e A335784 0, 0, 0, 0, 0, 0, 1;
%e A335784 18;
%e A335784 36, 81, 9, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1;
%e A335784 126, 36;
%e A335784 180, 135, 18, 45, 9, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1;
%e A335784 288, 126, 54;
%e A335784 90, 36, 18, 9, 0, 0, 1;
%e A335784 450, 306, 72, 18;
%e A335784 576, 369, 207, 126, 0, 9, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1;
%Y A335784 Cf. A332427 (n-sected sides, not angles), A335781 (regions), A335782 (vertices), A335783 (edges).
%K A335784 tabf,nonn
%O A335784 1,8
%A A335784 _Lars Blomberg_, Jun 24 2020