Problem 1073

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Statement. Let $A(x)$ count the number of composite $u<x$ such that $n!+1\equiv 0\pmod{u}$ for some $n$. Is it true that $A(x)\leq x^{o(1)}$?

Status. Open.

Source. erdosproblems.com/1073, accessed 2026-09-04. Cite as: T. F. Bloom, Erdős Problem #1073, https://www.erdosproblems.com/1073.

References.

• [HaSu02] Hardy, G. E. and Subbarao, M. V., A modified problem of Pillai and some related questions. Amer. Math. Monthly (2002), 554-559.

Formalization. Statement in formal-conjectures.

Progress

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Known Results

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Linked library material

These entries are derived from explicit links on library pages. They are navigation only and do not by themselves record mathematical progress.

• hardy_2002_modified_problem_pillai_related_questions
• hardy_2002_modified_problem_pillai_related_questions / problem_f