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.

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A334616 Number of 2-colorings of an n X n X n grid, up to rotational symmetry.

Original entry on oeis.org

2, 23, 5605504, 768614338020786176, 1772303994379887844373479205703254016, 4388012152856549445746584486819723041078276071004502223505850368, 746581580725934736852480760189481426040548499078234470565449222456544381939194522144498021170453413888
Offset: 1

Views

Author

Paul Oelkers, Sep 08 2020

Keywords

Comments

The cycle index of the permutation group is given by:
Even n: (1/24)*(s_1^n^3 + 8*s_1^n*s_3^((n^3-n)/3) + 6*s_2^(n^3/2) + 6*s_4^(n^3/4) + 3*s_2^(n^3/2));
Odd n: (1/24)*(s_1^n^3 + 8*s_1^n*s_3^((n^3-n)/3) + 6*s_1^n*s_2^((n^3-n)/2) + 6*s_1^n*s_4^((n^3-n)/4) + 3*s_1^n*s_2^((n^3-n)/2)).

Examples

			a(2)=23 from:
  00 00
  00 00
------------------------------------------
  10 00
  00 00
------------------------------------------
  11 00   10 00   10 01   10 00
  00 00   01 00   00 00   00 01
------------------------------------------
  11 00   11 00   01 10
  10 00   00 10   10 00
------------------------------------------
  11 00   11 00   01 10   11 00   11 10
  11 00   10 01   10 01   00 11   10 00
------------------------------------------
  00 11   00 11   10 01
  01 11   11 01   01 11
------------------------------------------
  00 11   01 11   01 10   01 11
  11 11   10 11   11 11   11 10
------------------------------------------
  01 11
  11 11
------------------------------------------
  11 11
  11 11
------------------------------------------
An example for the 2-coloring of the 3 X 3 X 3 grid can be written as:
  110 000 111
  100 000 111
  100 000 111
This coloring is equivalent to:
  111 000 111
  001 000 111
  000 000 111
  because you can get this configuration by rotating the first coloring by 90 degrees.
But it is different from:
  011 000 111
  001 000 111
  001 000 111
  because reflections are not considered.
		

Crossrefs

This is the three-dimensional version of A047937.
Cf. A000543.

Formula

a(n) = (1/24)*(2^n^3 + 6*2^((n^3)/4) + 9*2^((n^3)/2) + 8*2^((n^3-n)/3+n)) for n even;
a(n) = (1/24)*(2^n^3 + 6*2^(((n^3)-n)/4+n) + 9*2^(((n^3)-n)/2+n) + 8*2^(((n^3-n)/3)+n)) for n odd.

Extensions

More terms from Stefano Spezia, Sep 09 2020

A237748 Number of different ways to color the vertices of an n-dimensional hypercube using at most 2 colors.

Original entry on oeis.org

4, 6, 23, 496, 2275974, 800648638402240, 1054942853799126580390222487977120, 22436153203535039105819651040959324360753617244078062654624560815030272
Offset: 1

Views

Author

Seiichi Azuma, Feb 12 2014

Keywords

Comments

Two colorings are regarded as the same if they are conjugated by a permutation of the vertices caused by a rotation of the hypercube.
Regarding mirrored coloring also as the same, the number of ways appears to be given by A000616. - Seiichi Azuma, Feb 14 2014

Examples

			For n=2, there are 6 patterns to color the vertices of the square:
..1..1....1..1....1..1....1..0....1..0....0..0
..1..1....1..0....0..0....0..1....0..0....0..0
For example, the next pattern is regarded as the same with the 3rd one above:
..1..0
..1..0
		

Crossrefs

Cf. A000543.
Column 2 of A325012.

A316093 Non-isomorphic colorings of the cube under rotations, using at most N colors on the faces and M colors on the vertices. Square array H(N,M) with N,M > 0 read by antidiagonals.

Original entry on oeis.org

1, 10, 23, 57, 776, 333, 240, 8121, 17946, 2916, 800, 44608, 200961, 176160, 16725, 2226, 168675, 1124208, 1995852, 1045050, 70911, 5390, 501528, 4281300, 11198720, 11877825, 4485960, 241913, 11712, 1261701, 12773538, 42697300, 66700400, 51044337, 15385706, 701968, 23355, 2807296, 32195646, 127461216, 254387500, 286724160, 175153881, 44761216, 1798281, 43450, 5685903, 71718336, 321364540, 759518850, 1093653675, 983988208, 509689776, 114826410, 4173775
Offset: 1

Views

Author

Marko Riedel, Jun 24 2018

Keywords

Examples

			Square array begins:
     1,     10,      57,      240,      800, ...
    23,    776,    8121,    44608,   168675, ...
   333,  17946,  200961,  1124208,  4281300, ...
  2916, 176160, 1995852, 11198720, 42697300, ...
		

Crossrefs

H(N,1) (first row) is A047780. H(1,M) (first column) is A000543.

Formula

H(N,M) = (1/24) (N^6 M^8 + 6 N^3 M^2 + 3 N^4 M^4 + 8 N^2 M^4 + 6 N^3 M^4).
Cycle index is (1/24)*(a1^6 b1^8 + 6 a1^2 a4 b4^2 + 3 a1^2 a2^2 b2^4 + 8 a3^2 b1^2 b3^2 + 6 a2^3 b2^4).
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