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A291188 Number of inequivalent 2 X n Sudoku grids ((2*n) X (2*n) grids divided into 2 X n boxes). 1
2, 49, 1673187, 4743933602050718 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

COMMENTS

We regard two grids as inequivalent if one cannot be transformed into another by some sequence of symmetries, or by relabelling. For the 2 X 3 Sudoku grids case the allowed equivalences are (see link to Jarvis):

- relabeling entries; reflection; rotation;

- permutation of blocks of columns 1-2, 3-4 and 5-6;

- permutation of blocks of rows 1-3 and 4-6;

- permutation of columns 1-2;

- permutation of columns 3-4;

- permutation of columns 5-6;

- permutation of rows 1-3;

- permutation of rows 4-6.

LINKS

Table of n, a(n) for n=2..5.

Frazer Jarvis, Sudoku enumeration problems

Jordy Vanpoucke, Mutually orthogonal latin squares and their generalizations

EXAMPLE

a(2) = 2:

12|34  12|34

34|12  34|12

--+--  --+--

21|43  23|41

43|21  41|23

--------------------------------

An example of 2 X 3 Sudoku grids:

14|25|36

35|16|24

26|34|15

--+--+--

41|52|63

52|63|41

63|41|52

CROSSREFS

Cf. A109741, A291187.

Sequence in context: A269839 A088067 A145676 * A225795 A027619 A076267

Adjacent sequences:  A291185 A291186 A291187 * A291189 A291190 A291191

KEYWORD

nonn,more

AUTHOR

Seiichi Manyama, Aug 19 2017

STATUS

approved

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Last modified October 14 08:54 EDT 2019. Contains 327995 sequences. (Running on oeis4.)