Tail/arc-compression search with hard threshold a > N/3. Started from the previous size-29 record, translated a dense cyclic arc into the permitted upper region, then used neutral tail-preserving local moves to escape the rigid starting state. A direct insertion then produced this size-30 witness; every element is > N/3.
Yongxi (Aaron) Lin · 2026-08-09 20:42:15 UTC