Erdős problem 888 · problems.science

What is the size of the largest $A\subseteq \{1,\ldots,n\}$ such that if $a\leq b\leq c\leq d\in A$ are such that $abcd$ is a square then $ad=bc$ ?

No current result

No reviewed Result is current in Vela Mathematics Program. Retained source material is shown below.

FormalConjectures/ErdosProblems/888.lean

Formal Conjectures

FormalConjectures/ErdosProblems/888.leanErdos888.erdos_8881 lineExact file

1(fun n => ↑(Nat.findGreatest (Erdos888.p n) n)) =Θ[Filter.atTop] fun n => ↑n * Real.log (Real.log ↑n) / Real.log ↑n

SolvedStatement only, no proof

Work these sources record against this Problem. Source-reported attribution, not reviewed here.

AI standalone
Erdős AI contributions wiki · 18 Jan, 2026
Machine
Claude Opus 4.5, Gemini 3 Pro, GPT-5.2 Thinking
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AI collaborating with humans
Erdős AI contributions wiki · 25 Apr, 2026
Machine
Aristotle, GPT-5.5 Pro
People
Przemek Chojecki
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Subtle errors
GPT-Erdős
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argument
VibeMathed
Machine
Aristotle, GPT-5.5 Pro
People
Przemek Chojecki
Reported outcome
resolved
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