==> competition/games/chess/knight.most.s <==
n^2/2 for n even >= 4.

Divide the board in parts of 2x4 squares. The squares within
each part are paired as follows:

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|A|B|
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|C|D|
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|B|A|
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|D|C|
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Clearly, not more than one square per pair can be occupied by a knight.