Every problem here was open when it entered the pool.
Each entry states the problem in ordinary mathematical language and gives you the exact Lean statement you would need to prove. Nothing is paraphrased, so what you read is what gets checked.
Number theory
Erdős problem 373
Show that the equation n!=a_1!a_2!···a_k!, with n−1 > a_1 ≥ a_2 ≥ ··· ≥ a_k, has
only finitely many solutions.
$2,158 bounty·1 piece from 1 person·last one 18 days ago
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28 Sept 2025a year of work on this problem20 Sept 2026
Solve it
A complete proof or refutation in Lean. The first one the validator accepts takes the whole bounty.
A statement that does not faithfully capture the original conjecture is the one real risk here, so we would rather hear about it early - before someone spends weeks on it.
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