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9 open problems · 9 with Lean statements

Open problems about factorials

Equations and divisibility questions involving n!, products of consecutive integers, and their prime factors.

Level A · Machine-checkable Hard Lean statement

Erdős Problem #1108

For each k ≥ 2, does the set A = Σ_n∈ Sn! : S⊂ ℕ finite of all finite sums of distinct factorials contain only finitely many k-th powers?

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Level A · Machine-checkable Hard Lean statement

Erdős Problem #18

Conjecture 1. Are there infinitely many practical numbers m such that h(m) < (log log m)^O(1)? More precisely: does there exist a constant C > 0 such that for infinitely many practical numbers m, we have h(m) < (log log m)^C?

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Level A · Machine-checkable Hard Lean statement

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.

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Level A · Machine-checkable Hard Lean statement

Erdős Problem #398

Brocard's Problem Does n! + 1 = m^2 have integer solutions other than n = 4, 5, 7?

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Level A · Machine-checkable Hard Lean statement

Erdős Problem #478

Let p be a prime and A_p = k! pmodp : 1≤ k<p. Is it true that lvert A_prvert ∼ (1-1/e)p?

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Level A · Machine-checkable Hard Lean statement

Erdős Problem #912

Prove that there exists some c>0 such that h(n) ∼ c (n/log n)^1/2 as n→ ∞.

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