cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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.

Original entry on oeis.org

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

Views

Author

Lars Blomberg, Jun 24 2020

Keywords

Comments

For n<=200 no polygon has more than 18 edges.
See A335781 for illustrations.

Examples

			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).