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 1-6 of 6 results.

A338622 Irregular table read by rows: The number of k-faced polyhedra, where k>=4, formed when the five Platonic solids, in the order tetrahedron, octahedron, cube, icosahedron, dodecahedron, are internally cut by all the planes defined by any three of their vertices.

Original entry on oeis.org

1, 8, 72, 24, 2160, 360, 205320, 208680, 94800, 34200, 7920, 1560, 120
Offset: 1

Views

Author

Scott R. Shannon, Nov 04 2020

Keywords

Comments

See A338571 for further details and images of this sequence.
The author thanks Zach J. Shannon for producing the images for this sequence.

Examples

			The cube is cut with 14 internal planes defined by all 3-vertex combinations of its 8 vertices. This leads to the creation of 72 4-faced polyhedra and 24 5-faced polyhedra, 96 pieces in all. See A338571 and A333539.
The table is:
1;
8;
72, 24;
2160, 360;
205320, 208680, 94800, 34200, 7920, 1560, 120;
		

Crossrefs

Cf. A338571 (total number of polyhedra), A333539 (n-dimensional cube), A053016, A063722, A063723, A098427, A333543.

Formula

Sum of row n = A338571(n).

A338571 Number of polyhedra formed when the five Platonic solids, in the order tetrahedron, octahedron, cube, icosahedron, dodecahedron, are internally cut by all the planes defined by any three of their vertices.

Original entry on oeis.org

1, 8, 96, 2520, 552600
Offset: 1

Views

Author

Scott R. Shannon, Nov 03 2020

Keywords

Comments

For a Platonic solid create all possible planes defined by connecting any three of its vertices. For example, in the case of a cube this results in fourteen planes; six planes between the pairs of parallel edges connected to each end of the face diagonals, and eight planes from connecting the three vertices adjacent to each corner vertex. Use all the resulting planes to cut the solid into individual smaller polyhedra. The sequence lists the numbers of resulting polyhedra for the Platonic solids, ordered by number of vertices: tetrahedron, octahedron, cube, icosahedron, dodecahedron.
See A338622 for the number and images of the k-faced polyhedra in each dissection for each of the five solids.
The author thanks Zach J. Shannon for producing the images for this sequence.

Examples

			a(1) = 1. The tetrahedron has no internal cutting planes so the single polyhedron after cutting is the tetrahedron itself.
a(2) = 8. The octahedron has 3 internal cutting planes resulting in 8 polyhedra.
a(3) = 96. The cube has 14 internal cutting planes resulting in 96 polyhedra. See also A333539.
a(4) = 2520. The icosahedron has 47 cutting planes resulting in 2520 polyhedra.
See A338622 for a breakdown of the above totals into the corresponding number of k-faced polyhedra.
a(5) = 552600. The dodecahedron has 307 internal cutting planes resulting in 552600 polyhedra. It is the only Platonic solid which produces polyhedra with 6 or more faces.
		

Crossrefs

Cf. A338622 (number of k-faced polyhedra in each dissection), A333539 (n-dimensional cube), A053016, A063722, A063723, A098427.

A198861 The number of ways to paint the faces of the five Platonic solids using exactly n colors where n is the number of faces of each solid.

Original entry on oeis.org

2, 30, 1680, 7983360, 40548366802944000
Offset: 1

Views

Author

Geoffrey Critzer, Oct 30 2011

Keywords

Comments

Let G, the group of rotations in 3 dimensional space act on the set of n! paintings of each Platonic solid having n faces. There are n! fixed points in the action table since the only element in G that leaves a painting fixed is the identity element. The order of G is A098427/2. So by Burnside's Lemma a(n)=n!/|G|.

Crossrefs

Cf. A053016 (number of faces), A063722 (number of edges).

Programs

  • PARI
    lista() = {ve = [6, 12, 12, 30, 30 ]; vf = [4, 6, 8, 12, 20 ]; for (i=1, 5, nb = vf[i]!/(2*ve[i]); print1(nb, ", "););} \\ Michel Marcus, Aug 25 2014

Formula

a(n) = A053016(n)!/(2*A063722(n)) (see link). - Michel Marcus, Aug 24 2014

A273509 Orders of the symmetry groups of the six convex regular 4-polytopes, in the order 5-cell, 8-cell, 16-cell, 24-cell, 120-cell, 600-cell.

Original entry on oeis.org

120, 384, 384, 1152, 14400, 14400
Offset: 1

Views

Author

Felix Fröhlich, May 23 2016

Keywords

Crossrefs

Cf. A098427.

A317978 The number of ways to paint the cells of the six convex regular 4-polytopes using exactly n colors where n is the number of cells of each 4-polytope.

Original entry on oeis.org

2, 210, 108972864000, 1077167364120207360000
Offset: 1

Views

Author

Frank M Jackson, Aug 12 2018

Keywords

Comments

Let G, the group of rotations in 4 dimensional space, act on the set of n! paintings of each convex regular 4-polytopes having n cells. There are n! fixed points in the action table since the only element in G that leaves a painting fixed is the identity element. The order of G is A273509/2. So by Burnside's Lemma a(n)=n!/|G|. a(5) = 120!/7200 and a(6) = 600!/72000 and they are too large to display.
See A198861 for the Platonic solids which are the analogs of the regular polyhedra in three dimensions.
a(6) = 17577...66368*10^146 has 1405 digits. - Georg Fischer, Jun 16 2025

Examples

			The second of these six 4-polytopes (in sequence of cell count) is the 4-cube (with 8 cells). It has |G| = 192 rotations with n = 8. Hence a(2) = 8!/192 = 210.
		

Crossrefs

Programs

  • Maple
    {5!/60, 8!/192, 16!/192, 24!/576, 120!/7200, 600!/7200};
  • Mathematica
    {5!/60, 8!/192, 16!/192, 24!/576, 120!/7200, 600!/7200}

Formula

a(n) = 2*A063924(n)! / A273509(n). [Corrected by Georg Fischer, Jun 16 2025]

A343212 Order of the symmetry group of the n-th Johnson solid.

Original entry on oeis.org

8, 10, 6, 8, 10, 10, 6, 8, 10, 8, 10, 12, 20, 12, 16, 20, 16, 6, 8, 10, 10, 6, 8, 10, 10, 8, 12, 16, 16, 20, 20, 10, 10, 20, 12, 12, 16, 20, 20, 10, 10, 20, 20, 6, 8, 10, 5, 10, 4, 4, 12, 4, 4, 4, 8, 4, 12, 10, 20, 4, 6, 4, 6, 6, 6, 8, 16, 10, 20, 4, 6, 10, 20, 4, 6, 10, 10, 2, 2, 20, 4, 2, 6, 8, 16, 4, 2, 4, 4, 8, 8, 6
Offset: 1

Views

Author

Pontus von Brömssen, Apr 08 2021

Keywords

Examples

			The gyrobifastigium (J26) has a(26) = 8 symmetries.
		

Crossrefs

Showing 1-6 of 6 results.