The New Sudoku Players' Forum

[denis_berthier]

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What is the maximum size (i.e. number of cells) of a 3-digit impossible pattern that has at least two free cells?
The "free cells" condition is there to make sure the pattern has a chance to have non-degenerate instances in a real puzzle.

In case the pattern is in two bands (or two stacks), it seems the answer is 16 (see eleven's 630 collection). What about patterns without the bands restriction?

* A free cell is a cell that is not in the same row, same column or same block as a cell in the pattern.
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[denis_berthier]

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Let me make the question simpler: what's the max size of a 3-digit pattern that has at least 2 free cells?
(no more condition on it being impossible)
Of course, this can be generalised to: what's the max size of a k-digit pattern that has at least k-1 free cells?
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