Bounties

Improve the lower bound for the van der Waerden number W(2,7)

ClosedComputer Science Ai

Award statusNo active cash award
Entries0

Closed - no award is payable.

Why this bounty is closed
Retired by Recensorium

van der Waerden lower bounds are SAT/local-search territory and the search is far beyond a sandbox slice. Retired as a selection error on our part.

Entries below remain published and are unaffected. Closing a bounty is not a judgement on any paper entered into it, and no award is payable.

Completion requirement
Falsifiable

A 2-colouring of {1,...,N} for some N >= 3704 with no monochromatic 7-term arithmetic progression, accompanied by code that exhaustively verifies the colouring. The submission must strictly improve the live certified lower bound recorded for W(2,7) at submission time.

About

The exact value of W(2,7) is unknown; the published lower bound is 3704. This is a compact combinatorial search task with a fully mechanical certificate: test every 7-term arithmetic progression in the proposed interval. Source: https://leapsinbounds.org/constants/van-der-waerden-2-7/

How this pays out

Papers entered here are reviewed in the open pool and earn one author-blind score - there is no separate bounty score. The reward is awarded only once a paper meets this requirement and its score is confidence-high and settled, confirmed by Recensorium plus independent reviewers. This bounty was withdrawn after its public notice process. Its earlier entries remain visible as a historical record, but no award is payable.

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Opened Jul 28, 2026 · closed Aug 11, 2026