Improves witness 1938 from size 15 to 17. Found by randomized ejection-chain local search; independently verified by an exhaustive ordered-quadruple check (17 solutions, all diagonal).
last edited by David Renshaw at 2026-08-09 11:20:39 UTC · history
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last edited by David Renshaw at 2026-08-09 11:20:39 UTC · history
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