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.

Showing 1-4 of 4 results.

A332421 The number of regions inside a nonagon formed by the straight line segments mutually connecting all vertices and all points that divide the sides into n equal parts.

Original entry on oeis.org

154, 2754, 16858, 55098, 142318, 298350, 568162, 975294, 1585666, 2426292, 3588508, 5093604, 7067422, 9523746, 12612214, 16351218, 20924029, 26326026, 32789107, 40289238, 49093282, 59181228, 70852528
Offset: 1

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Author

Keywords

Comments

The terms are from numeric computation - no formula for a(n) is currently known.

Crossrefs

Cf. A332427 (n-gons), A332428 (vertices), A332429 (edges), A007678, A092867, A331452, A331929.

Extensions

a(6)-a(23) from Lars Blomberg, May 16 2020

A332428 The number of vertices on a nonagon formed by the straight line segments mutually connecting all vertices and all points that divide the sides into n equal parts.

Original entry on oeis.org

135, 2395, 16434, 53155, 141147, 293374, 565767, 966493, 1580940, 2411533, 3581613, 5070655, 7057026, 9493435, 12594564, 16307974, 20902338, 26269597, 32760774, 40217905, 49049919, 59090671, 70803180
Offset: 1

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Author

Keywords

Comments

See the links in A332421 for images of the nonagons.

Crossrefs

Cf. A332421 (regions), A332427 (n-gons), A332429 (edges), A330846, A092866, A332599, A007569.

Extensions

a(6)-a(23) from Lars Blomberg, May 16 2020

A332429 The number of edges on a nonagon formed by the straight line segments mutually connecting all vertices and all points that divide the sides into n equal parts.

Original entry on oeis.org

288, 5148, 33291, 108252, 283464, 591723, 1133928, 1941786, 3166605, 4837824, 7170120, 10164258, 14124447, 19017180, 25206777, 32659191, 41826366, 52595622, 65549880, 80507142, 98143200, 118271898, 141655707
Offset: 1

Views

Author

Keywords

Comments

See the links in A332421 for images of the nonagons.

Crossrefs

Cf. A332421 (regions), A332427 (n-gons), A332428 (vertices), A330845, A274586, A332600, A331765.

Extensions

a(6)-a(23) from Lars Blomberg, May 16 2020

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).
Showing 1-4 of 4 results.