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A211172 A Sudoku torus. 1
6, 5, 7, 3, 4, 2, 1, 9, 8, 9, 8, 1, 5, 6, 7, 4, 3, 2, 3, 2, 4, 8, 9, 1, 6, 5, 7, 5, 7, 6, 2, 3, 4, 9, 8, 1, 8, 1, 9, 7, 5, 6, 3, 2, 4, 2, 4, 3, 1, 8, 9, 5, 7, 6, 7, 6, 5, 4, 2, 3, 8, 1, 9, 1, 9, 8, 6, 7, 5, 2, 4, 3, 4, 3, 2, 9, 1, 8, 7, 6, 5 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The sequence is a listing for a Sudoku grid:

6 5 7 3 4 2 1 9 8

9 8 1 5 6 7 4 3 2

3 2 4 8 9 1 6 5 7

5 7 6 2 3 4 9 8 1

8 1 9 7 5 6 3 2 4

2 4 3 1 8 9 5 7 6

7 6 5 4 2 3 8 1 9

1 9 8 6 7 5 2 4 3

4 3 2 9 1 8 7 6 5

No two diagonally adjacent elements are the same. If the grid is rolled into a cylinder either way, this is still true making a 'Sudoku torus'.

This extra information can be used to construct puzzles that use 'no diagonal' logic.

The two lexicographical Sudoki in the cross-references have one internal diagonal each and several external diagonals.

LINKS

Table of n, a(n) for n=1..81.

Mathworld, Sudoku

Wikipedia, Sudoku

EXAMPLE

If a puzzle has say:

   |x

  5|

___|x

then x cannot be 5.

CROSSREFS

Cf. A107739.

Cf. A114288, A112454 (lexicographic grids).

Sequence in context: A195786 A201330 A089826 * A152149 A196400 A086268

Adjacent sequences:  A211169 A211170 A211171 * A211173 A211174 A211175

KEYWORD

nonn,fini,full,tabf

AUTHOR

Jon Perry, Jan 31 2013

STATUS

approved

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Last modified October 19 22:00 EDT 2018. Contains 316378 sequences. (Running on oeis4.)