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 1-10 of 11 results. Next

A331931 The number of regions inside a hexagon 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

24, 408, 2268, 8208, 20832, 44640, 89214, 154752, 249906, 390012, 590658, 824712, 1183704, 1580868, 2067162, 2770476, 3585582, 4397172, 5665818, 6827736, 8318976, 10209948, 12364098, 14395164, 17194230, 20216808, 23436612, 27124416, 31817676, 35516328
Offset: 1

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Keywords

Comments

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

Crossrefs

Cf. A331932 (n-gons), A330845 (edges), A330846 (vertices), A007678, A092867, A331452, A331929.

Extensions

a(9)-a(30) from Lars Blomberg, May 12 2020

A330845 The number of edges inside a hexagon 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

42, 708, 4020, 15120, 38544, 83136, 169686, 294678, 475500, 746340, 1140624, 1581612, 2296986, 3055734, 3980526, 5391264, 7003662, 8516346, 11094810, 13280970, 16180932, 19971282, 24277212, 28090218, 33683862, 39656604, 45901494, 53121744, 62678268, 69382632
Offset: 1

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Author

Keywords

Comments

See the links in A331931 for images of the hexagons.

Crossrefs

Cf. A331931 (regions), A331932 (n-gons), A330846 (vertices), A274586 , A332600, A331765.

Extensions

a(9)-a(30) from Lars Blomberg, May 12 2020

A330847 The number of vertices inside a pentagon 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

10, 121, 1055, 3506, 10410, 21111, 43740, 74526, 124490, 190291, 288190, 403321, 573805, 771191, 1027550, 1331896, 1721765, 2157301, 2712175, 3322441, 4067325, 4904491, 5900185, 6975151, 8268755, 9678566, 11297345, 13060231, 15102955, 17263311, 19784995
Offset: 1

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Author

Keywords

Comments

See the links in A331929 for images of the pentagons.

Crossrefs

Cf. A331929 (regions), A331939 (n-gons), A329710 (edges), A330846, A092866, A332599, A007569

Extensions

a(9) and beyond from Lars Blomberg, May 11 2020

A331932 Triangle read by rows: Take a hexagon with all diagonals drawn, as in A331931. Then T(n,k) = number of k-sided polygons in that figure for k = 3, 4, ..., n+4.

Original entry on oeis.org

18, 6, 0, 264, 108, 36, 0, 1344, 654, 252, 12, 6, 4164, 2772, 1020, 228, 24, 0, 10038, 7758, 2424, 516, 72, 24, 0, 21108, 16188, 6060, 1128, 156, 0, 0, 0, 39690, 32022, 13368, 3654, 432, 48, 0, 0, 0, 68052, 56616, 22980, 6084, 888, 120, 12, 0, 0, 0
Offset: 1

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Author

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Comments

See the links in A331931 for images of the hexagons.

Examples

			A hexagon with no other points along its edges, n = 1, contains 18 triangles, 6 quadrilaterals and no other n-gons, so the first row is [18,6,0]. A hexagon with 1 point dividing its edges, n = 2, contains 264 triangles, 108 quadrilaterals, 36 pentagons and no other n-gons, so the second row is [264,108,36,0].
Triangle begins:
  18,6,0
  264,108,36,0
  1344,654,252,12,6
  4164,2772,1020,228,24,0
  10038,7758,2424,516,72,24,0
  21108,16188,6060,1128,156,0,0,0
  39690,32022,13368,3654,432,48,0,0,0
  68052,56616,22980,6084,888,120,12,0,0,0
The row sums are A331931.
		

Crossrefs

Cf. A331931 (regions), A330845 (edges), A330846 (vertices), A331906, A007678, A092867, A331452.

A332418 The number of vertices on a decagon 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

171, 3581, 23651, 80191, 213041, 444251, 862711, 1481141, 2413721, 3701951, 5493891, 7765621, 10833601, 14589491, 19315751, 25064491, 32107771, 40337021, 50328771, 61790891, 75318371
Offset: 1

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Keywords

Comments

See the links in A333139 for images of the decagons.

Crossrefs

Cf. A333139 (regions), A332417 (n-gons), A332419 (edges), A330846, A092866, A332599, A007569.

Extensions

a(6)-a(21) from Lars Blomberg, May 18 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

A333109 The number of vertices on an octagon 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

57, 1145, 8417, 29121, 80345, 167105, 333297, 570969, 939113, 1441153, 2153937, 3029913, 4262929, 5741473, 7606745, 9876585, 12690553, 15921777, 19922289, 24430633, 29834073, 35990065, 43151521, 51068689
Offset: 1

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Author

Keywords

Comments

See the links in A333075 for images of the octagons.

Crossrefs

Cf. A333075 (regions), A333076 (n-gons), A333110 (edges), A330846, A092866, A332599, A007569.

Extensions

a(7)-a(24) from Lars Blomberg, May 14 2020

A333113 The number of vertices inside a heptagon 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

42, 708, 5369, 17417, 47796, 99261, 194278, 331955, 546805, 833946, 1245314, 1762265, 2461837, 3311680, 4402405, 5700598, 7322231, 9200878, 11494161, 14108123, 17224438, 20752264, 24894009, 29506128, 34854099, 40780391, 47552050
Offset: 1

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Keywords

Comments

See the links in A329713 for images of the heptagons.

Crossrefs

Cf. A329713 (regions), A329714 (n-gons), A333112 (edges), A330846, A092866, A332599, A007569.

Extensions

a(8)-a(27) from Lars Blomberg, May 13 2020

A357197 Number of vertices in a hexagon when n internal hexagons are drawn between the 6n points that divide each side into n+1 equal parts.

Original entry on oeis.org

6, 12, 30, 60, 102, 156, 222, 300, 390, 468, 606, 708, 870, 1020, 1152, 1356, 1542, 1740, 1950, 2112, 2406, 2652, 2910, 3072, 3462, 3756, 4062, 4350, 4710, 4974, 5406, 5772, 6126, 6540, 6918, 7260, 7782, 8220, 8646, 8946, 9606, 10032, 10590, 11052, 11568, 12156, 12702, 13116, 13830, 14388
Offset: 0

Views

Author

Scott R. Shannon, Sep 17 2022

Keywords

Comments

Unlike similar dissections of the triangle and square, see A357007 and A357060, there is no obvious pattern for n values that yield hexagons with non-simple intersections; these n values begin 9, 11, 14, 19, 23, 27, 29, 32, 34, 35, 38, 39, 41, 43, ... .

Crossrefs

Cf. A357196 (regions), A357198 (edges), A330846, A357007 (triangle), A357060 (square).

Formula

a(n) = A357198(n) - A357196(n) + 1 by Euler's formula.
Conjecture: a(n) = 6*n^2 + 6 for hexagons that only contain simple intersections when cut by n internal hexagons.

A335734 a(n) is the number of vertices formed by n-secting the angles of a hexagon.

Original entry on oeis.org

6, 7, 66, 19, 186, 145, 384, 199, 642, 547, 978, 631, 1332, 1231, 1824, 1351, 2298, 2191, 2952, 2281, 3546, 3415, 4356, 3583, 5070, 4849, 6036, 5101, 6858, 6583, 7968, 6901, 8928, 8611, 10152, 8965, 11250, 10897, 12606, 11257, 13824, 13459, 15336, 13903, 16692
Offset: 1

Views

Author

Lars Blomberg, Jun 21 2020

Keywords

Crossrefs

Cf. A330846 (n-sected sides, not angles), A335733 (regions), A335735 (edges), A335736 (ngons).
Showing 1-10 of 11 results. Next