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.

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

Offset

1,8

Comments

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

See A335781 for illustrations.

Links

Lars Blomberg, Table of n, a(n) for n = 1..2217 (the first 200 rows)

Example

The table begins:
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, 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;
576, 369, 207, 126, 0, 9, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1;

Crossrefs

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

Sequence in context: A204824 A252424 A327774 * A347889 A375679 A376437

Adjacent sequences: A335781 A335782 A335783 * A335785 A335786 A335787

Keyword

tabf,nonn

Author

Lars Blomberg, Jun 24 2020

Status

approved