witness #1997

N: 686
|A|: 17
exponent log |A| / log N: 0.4338

status: current record for this modulus
submitted by: David Renshaw
submitted at: 2026-08-09 11:26:58 UTC

Elements (17)

5, 7, 47, 54, 55, 136, 153, 157, 297, 341, 343, 391, 489, 493, 572, 633, 654

Commentary

Improves witness 1936 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 11:26:58 UTC · history