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A109741 Number of inequivalent (completed) n^2 X n^2 sudokus (or Sudokus). 5
1, 1, 2, 5472730538 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
COMMENTS
See A107739 for definition of an n^2 X n^2 sudoku.
a(2) = 2 independently computed by Gary McGuire and Hugo van der Sanden.
For the 9 X 9 case the allowed equivalences are (see link to Jarvis et al.):
- relabeling entries; reflection; rotation;
- permutation of blocks of columns 1-3, 4-6 and 7-9;
- permutation of blocks of rows 1-3, 4-6 and 7-9;
- permutation of columns 1-3; permutation of rows 1-3;
- permutation of columns 4-6; permutation of rows 4-6;
- permutation of columns 7-9; permutation of rows 7-9.
See A107739 for the total number of ("square") sudoku grids, A114288 for the lexicographically earliest 9 X 9 solution. - M. F. Hasler, Mar 29 2013
REFERENCES
J.-P. Delahaye, "Le tsunami du Sudoku" in 'Pour La Science' (French Edition of "Scientific American"), December 2005 pp. 144-9, Paris.
LINKS
J. P. Grossman, Javascript Sudoku solver
Frazer Jarvis et al., Sudoku enumeration problems
Eric Weisstein's World of Mathematics, Sudoku
Wikipedia, Sudoku
EXAMPLE
a(2) = 2:
12|34 12|34
34|12 34|12
--+-- --+--
21|43 23|41
43|21 41|23
CROSSREFS
Sequence in context: A306499 A051241 A094486 * A105759 A154422 A154423
KEYWORD
nonn,bref,hard
AUTHOR
N. J. A. Sloane, Aug 13 2005
EXTENSIONS
Links to Jarvis et al. fixed by M. F. Hasler, Mar 29 2013
STATUS
approved

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Last modified May 25 07:15 EDT 2024. Contains 372782 sequences. (Running on oeis4.)