All open problems
Source labels openChecked July 26, 2026

Erdős ProblemsNumber theory

Erdős Problem 686

Can every integer N2N≥2 be written as N=1ik(m+i)1ik(n+i)N=\frac{\prod_{1\leq i\leq k}(m+i)}{\prod_{1\leq i\leq k}(n+i)} for some k2k≥2 and mn+km≥n+k?

Mathematical statement

Can every integer N2N≥2 be written as N=1ik(m+i)1ik(n+i)N=\frac{\prod_{1\leq i\leq k}(m+i)}{\prod_{1\leq i\leq k}(n+i)} for some k2k≥2 and mn+km≥n+k?

Statement source: Erdős Problems statement material

Statement terms: Source-specific

Source-specific terms. Therefore does not assert reuse rights beyond attributed display.

Statement artifacts, not proofs

These records expose exact Lean propositions and statement-only wrappers. Defining a proposition does not supply a proof of it. A placeholder-bearing target also contains no proof. Elaboration checks syntax and types; it does not certify that a formalization perfectly captures every nuance of the informal problem.

Pinned Lean formulation 1

erdos_686

Canonical source
Complete statement target, proof intentionally absentLean 4
theorem erdos_686 :    answer(sorry)   N  (2 : ), ᵉ (k  2) (n : ) (m  n + k),      (N : ) = (∏ i  Finset.Icc 1 k, (m + i)) / (∏ i  Finset.Icc 1 k, (n + i)) := by  sorry
Statement source
Formal Conjectures
Lean version
v4.27.0
Placeholder
Present; no proof artifact
Source evidence
Pinned source index
Fidelity review
Community formulation

References