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Cats on Cushions Puzzle

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Edited by Richard Walker, Friday, 13 Nov 2020, 02:15

This is a sawn-down version of a puzzle "Arranging cats and dogs" that Matt Parker recently posted on YouTube.

In our version we have a pair of cats, and eight cushions. We want to seat each cat on its own cushion, with the restriction that they cannot occupy adjacent cushions, in case they start a cat fight. Here is one possible arrangement.

You see the cats are not next to one another, so the rule is satisfied.

The question is: how many possible arrangements are there? What if there were 9 cushions? Or 10? Can you give a general formula?

Permalink 4 comments (latest comment by Richard Walker, Saturday, 14 Nov 2020, 21:09)
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