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 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. 4

%I

%S 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 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 576,369,207,126,0,9,0,0,0,0,0,0,0,0,0,1

%N 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 For n<=200 no polygon has more than 18 edges.

%C See A335781 for illustrations.

%H Lars Blomberg, <a href="/A335784/b335784.txt">Table of n, a(n) for n = 1..2217</a> (the first 200 rows)

%e The table begins:

%e 0, 0, 0, 0, 0, 0, 1;

%e 18;

%e 36, 81, 9, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1;

%e 126, 36;

%e 180, 135, 18, 45, 9, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1;

%e 288, 126, 54;

%e 90, 36, 18, 9, 0, 0, 1;

%e 450, 306, 72, 18;

%e 576, 369, 207, 126, 0, 9, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1;

%Y Cf. A332427 (n-sected sides, not angles), A335781 (regions), A335782 (vertices), A335783 (edges).

%K tabf,nonn

%O 1,8

%A _Lars Blomberg_, Jun 24 2020

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Last modified June 27 19:31 EDT 2022. Contains 354898 sequences. (Running on oeis4.)