A211172 A Sudoku torus.

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

Offset: 1

Author

Jon Perry, Jan 31 2013

Keywords

• nonn
• fini
• full
• tabf

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.

Examples

			If a puzzle has say:
   |x
  5|
___|x
then x cannot be 5.
		

Links

• Mathworld, Sudoku
• Wikipedia, Sudoku

Crossrefs

Cf. A107739.

Cf. A114288, A112454 (lexicographic grids).