

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
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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 crossreferences 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



