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
EXAMPLE
If a puzzle has say:
|x
5|
___|x
then x cannot be 5.
CROSSREFS
KEYWORD
nonn,fini,full,tabf
AUTHOR
Jon Perry, Jan 31 2013
STATUS
approved