A286393 -id:A286393 - cp's OEIS frontend

A343097 Array read by antidiagonals: T(n,k) is the number of k-colorings of an n X n grid, up to rotations and reflections.

1, 1, 0, 1, 1, 0, 1, 2, 1, 0, 1, 3, 6, 1, 0, 1, 4, 21, 102, 1, 0, 1, 5, 55, 2862, 8548, 1, 0, 1, 6, 120, 34960, 5398083, 4211744, 1, 0, 1, 7, 231, 252375, 537157696, 105918450471, 8590557312, 1, 0, 1, 8, 406, 1284066, 19076074375, 140738033618944, 18761832172500795, 70368882591744, 1, 0

Offset: 0

Andrew Howroyd, Apr 14 2021

			Array begins:
====================================================================
n\k | 0 1       2            3               4                 5
----+---------------------------------------------------------------
  0 | 1 1       1            1               1                 1 ...
  1 | 0 1       2            3               4                 5 ...
  2 | 0 1       6           21              55               120 ...
  3 | 0 1     102         2862           34960            252375 ...
  4 | 0 1    8548      5398083       537157696       19076074375 ...
  5 | 0 1 4211744 105918450471 140738033618944 37252918396015625 ...
  ...

Andrew Howroyd, Table of n, a(n) for n = 0..860

Rows 0..5 are A000012, A001477, A002817, A217331, A217338, A283033.
Columns 0..10 are A000007, A000012, A054247, A054739, A054751, A054752, A286392, A286393, A286394, A286396, A286397.
Main diagonal is A001326.
Cf. A246106, A343095, A343875.

T(n,k) = {(k^(n^2) + 2*k^((n^2 + 3*(n%2))/4) + k^((n^2 + (n%2))/2) + 2*k^(n*(n+1)/2) + 2*k^(n*(n+n%2)/2) )/8}

T(n,k) = (k^(n^2) + 2*k^((n^2 + 3*(n mod 2))/4) + k^((n^2 + (n mod 2))/2) + 2*k^(n*(n+1)/2) + 2*k^(n*(n + n mod 2)/2) )/8.

A286394 Number of inequivalent n X n matrices over GF(8) under action of dihedral group of the square D_4.

Original entry on oeis.org

1, 8, 666, 16912512, 35184646816768, 4722366500530551259136, 40564819207305653446303190876160, 22300745198530623151211847196048401987796992, 784637716923335095479473759060307277562325323313332617216

Offset: 0

María Merino, Imanol Unanue, Yosu Yurramendi, May 08 2017

nonn

Burnside's orbit-counting lemma.

María Merino, Table of n, a(n) for n = 0..33
M. Merino and I. Unanue, Counting squared grid patterns with Pólya Theory, EKAIA, 34 (2018), 289-316 (in Basque).

Column k=8 of A343097.

Cf. A054247, A054739, A054751, A054752, A286392, A286393.

a(n) = (1/8)*(8^(n^2) + 2*8^(n^2/4) + 3*8^(n^2/2) + 2*8^((n^2 + n)/2)) if n is even;

a(n) = (1/8)*(8^(n^2) + 2*8^((n^2 + 3)/4) + 8^((n^2 + 1)/2) + 4*8^((n^2 +n)/2)) if n is odd.

A287245 Number of inequivalent n X n matrices over GF(7) under action of dihedral group of the square D_4, with one-seventh each of 1's, 2's, 3's, 4's, 5's, 6's and 7's (ordered occurrences rounded up/down if n^2 != 0 mod 7).

Original entry on oeis.org

1, 1, 1, 11340, 2270280240, 27055587870486000, 21628439666761521875561280, 920451958269648700957746787694592000, 1914192808178753950843058828570207003149548000000, 216425158352284448578663515683744576588775769063470820304640000

Offset: 0

María Merino, Imanol Unanue, May 22 2017

nonn

Computed using Polya's enumeration theorem for coloring.

			For n = 3 the a(3) = 11340 solutions are colorings of 3 X 3 matrices in 7 colors inequivalent under the action of D_4 with exactly occurrences 2, 2, 1, 1, 1, 1, 1 of each color (coefficient of x1^2 x2^2 x3^1 x4^1 x5^1 x6^1 x7^1).

María Merino, Table of n, a(n) for n = 0..33
M. Merino and I. Unanue, Counting squared grid patterns with Pólya Theory, EKAIA, 34 (2018), 289-316 (in Basque).

Cf. A286393, A082963, A286447, A286525, A286526, A287239.

G.f.: g(x1,x2,x3,x4,x5,x6,x7)=1/8*(y1^(n^2)+2*y1^n*y2^((n^2-n)/2)+3*y2^(n^2/2)+2*y4^(n^2/4)) if n even and 1/8*(y1^(n^2)+4*y1^n*y2^((n^2-n)/2)+y1*y2^((n^2-1)/2)+2*y1*y4^((n^2-1)/4)) if n odd, where coefficient correspond to y1=Sum_{i=1..7} x_i, y2=Sum_{i=1..7} x_i^2, y4=Sum_{i=1..7} x_i^4 and occurrences of numbers are ceiling(n^2/7) for the first k numbers and floor(n^2/7) for the last (7-k) numbers, if n^2 = k mod 7.

A286396 Number of inequivalent n X n matrices over GF(9) under action of dihedral group of the square D_4.

Original entry on oeis.org

1, 9, 1035, 48700845, 231628411446741, 89737248564744874067889, 2816049943117424212512789695666175, 7158021121277935153545945911617993395398302485, 1473773072217322896440109113309952350877179744639518847951721

Offset: 0

María Merino, Imanol Unanue, Yosu Yurramendi, May 08 2017

nonn

Burnside's orbit-counting lemma.

María Merino, Table of n, a(n) for n = 0..32
M. Merino and I. Unanue, Counting squared grid patterns with Pólya Theory, EKAIA, 34 (2018), 289-316 (in Basque).

Column k=9 of A343097.

Cf. A054247, A054739, A054751, A054752, A286392, A286393, A286394.

Table[1/8*(9^(n^2) + 2*9^((n^2 + 3 #)/4) + (3 - 2 #)*9^((n^2 + #)/2) + (2 + 2 #)*9^((n^2 + n)/2)) &@ Boole@ OddQ@ n, {n, 0, 7}] (* Michael De Vlieger, May 12 2017 *)

a(n) = (1/8)*(9^(n^2) + 2*9^(n^2/4) + 3*9^(n^2/2) + 2*9^((n^2 + n)/2)) if n is even;

a(n) = (1/8)*(9^(n^2) + 2*9^((n^2 + 3)/4) + 9^((n^2 + 1)/2) + 4*9^((n^2 + n)/2)) if n is odd.

A286397 Number of inequivalent n X n matrices over an alphabet of size 10 under action of dihedral group of the square D_4.

Original entry on oeis.org

1, 10, 1540, 125512750, 1250002537502500, 1250000000501250002500000, 125000000000000250375000000250000000, 1250000000000000000005001250000000002500000000000

Offset: 0

María Merino, Imanol Unanue, Yosu Yurramendi, May 08 2017

nonn

Burnside's orbit-counting lemma.

María Merino, Table of n, a(n) for n = 0..20
M. Merino and I. Unanue, Counting squared grid patterns with Pólya Theory, EKAIA, 34 (2018), 289-316 (in Basque).

Column k=10 of A343097.

Cf. A054247, A054739, A054751, A054752, A286392, A286393, A286394, A286395.

Table[1/8*(10^(n^2) + 2*10^((n^2 + 3 #)/4) + (3 - 2 #)*10^((n^2 + #)/2) + (2 + 2 #)*10^((n^2 + n)/2)) &@ Boole@ OddQ@ n, {n, 7}] (* Michael De Vlieger, May 12 2017 *)

a(n) = (1/8)*(10^(n^2) + 2*10^(n^2/4) + 3*10^(n^2/2) + 2*10^((n^2 + n)/2)) if n is even;

a(n) = (1/8)*(10^(n^2) + 2*10^((n^2 + 3)/4) + 10^((n^2 + 1)/2) + 4*10^((n^2 + n)/2)) if n is odd.

cp's OEIS Frontend

A343097 Array read by antidiagonals: T(n,k) is the number of k-colorings of an n X n grid, up to rotations and reflections.

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A286394 Number of inequivalent n X n matrices over GF(8) under action of dihedral group of the square D_4.

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A287245 Number of inequivalent n X n matrices over GF(7) under action of dihedral group of the square D_4, with one-seventh each of 1's, 2's, 3's, 4's, 5's, 6's and 7's (ordered occurrences rounded up/down if n^2 != 0 mod 7).

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Examples

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Crossrefs

Formula

A286396 Number of inequivalent n X n matrices over GF(9) under action of dihedral group of the square D_4.

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Programs

Mathematica

Formula

A286397 Number of inequivalent n X n matrices over an alphabet of size 10 under action of dihedral group of the square D_4.

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Mathematica

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