Erdős Problem a Daythe open tracker

Erdős Problem #397

DISPROVED LEANdatabase updated 2026-01-10

The statement as posed is false. A solution has also been checked by machine, in Lean.

What the community database records, not our verdict. erdosproblems.com no longer shows statuses (why).

Are there only finitely many solutions to \[ \prod_i \binom{2m_i}{m_i}=\prod_j \binom{2n_j}{n_j} \] with the \(m_i,n_j\) distinct? Somani, using ChatGPT, has given a negative answer. In fact, for any \(a\geq 2\), if \(c=8a^2+8a+1\), \(\binom{2a}{a}\binom{4a+4}{2a+2}\binom{2c}{c}= \binom{2a+2}{a+1}\binom{4a}{2a}\binom{2c+2}{c+1}.\) Further families of solutions are given in the comments by SharkyKesa. This was earlier asked about in a [MathOverflow] question, in response to which Elkies also gave an alternative construction which produces solutions - at the moment it is not clear whether Elkies' argument gives infinitely many solutions (although Bloom believes that it can). This was formalized in Lean by Wu using Aristotle.
Statement as formalized in Formal Conjectures (Google DeepMind, Apache-2.0) · their label: research solved. The authoritative wording is on erdosproblems.com/397.
Prizenone
Topicsnumber theory, binomial coefficients
Statement in LeanFormal Conjectures
Solution in Leanyes
Original pageerdosproblems.com/397
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