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Open-problem statements, with their sources attached.

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Source labels openErdős Problems · Number theory

Erdős Problem 366

Are there any 22-full nn such that n+1n+1 is 33-full?

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Source labels openErdős Problems · Number theory

Erdős Problem 366: Three Two

Are there infinitely many 3-full nn such that n+1n+1 is 2-full?

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Source labels openErdős Problems · Number theory

Erdős Problem 366: Weaker

Are there any consecutive pairs of 33-full integers?

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Source labels openErdős Problems · Number theory

Erdős Problem 371

Let P(n)P(n) denote the largest prime factor of nn. Show that the set of nn with P(n+1)>P(n)P(n+1) > P(n) has density 12\frac{1}{2}.

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Source labels openErdős Problems · Number theory

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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Source labels openErdős Problems · Number theory

Erdős Problem 373: Maximal Solution

Hickerson conjectured the largest solution the equation n!=a_1!a_2!···a_k!, with n−1 > a_1 ≥ a_2 ≥ ··· ≥ a_k, is 16!=14!5!2!.

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Source labels openErdős Problems · Number theory

Erdős Problem 373: Suranyi

Surányi was the first to conjecture that the only non-trivial solution to a!b!=n! is 6!7!=10!.

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Source labels openErdős Problems · Number theory

Erdős Problem 375

Is Erdos375Prop true?

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Source labels openErdős Problems · Number theory

Erdős Problem 376

Are there infinitely many nn such that (2nn){2n\choose n} is coprime to 105105?

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Source labels openErdős Problems · Number theory

Erdős Problem 377

Is there some absolute constant C>0C > 0 such that

pn1p(2nn)1pC \sum_{p \leq n} 1_{p\nmid {2n \choose n}}\frac{1}{p} \leq C

for all nn?

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Source labels openErdős Problems · Number theory

Erdős Problem 383

Is it true that for every kk there are infinitely many primes pp such that the largest prime divisor of

i=0k(p2+i) \prod_{i = 0}^k (p ^ 2 + i)

is pp?

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Source labels openErdős Problems · Number theory

Erdős Problem 385: I

Let F(n) := \max\{m + p(m) \mid \textrm{m < n composite}\}\} where p(m)p(m) is the least prime divisor of mm. Is it true that F(n)>nF(n)>n for all sufficiently large nn?

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Source labels openErdős Problems · Number theory

Erdős Problem 385: Ii

Let F(n) := \max\{m + p(m) \mid \textrm{m < n composite}\}\} where p(m)p(m) is the least prime divisor of mm. Does F(n)nF(n) - n \to \infty as nn\to\infty?

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Source labels openErdős Problems · Number theory

Erdős Problem 385: Lb

A question of Erdős, Eggleton, and Selfridge, who write that in fact it is possible that this quantity is always at least n+(1o(1))nn+(1-o(1))\sqrt{n}

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Source labels openErdős Problems · Number theory

Erdős Problem 386

There is a kk, such that 2kn22 \le k \le n - 2 and (nk)\binom{n}{k} can be the product of consecutive primes infinitely often?

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Source labels openErdős Problems · Number theory

Erdős Problem 386: Forall

For all 2kn22 \le k \le n - 2, can (nk)\binom{n}{k} be the product of consecutive primes infinitely often?

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Source labels openErdős Problems · Number theory

Erdős Problem 386: Two

Can (n2)\binom{n}{2} be the product of consecutive primes infinitely often?

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Source labels openErdős Problems · Number theory

Erdős Problem 387: Schinzel

The following is Schinzel's conjecture, which appears in [Gu04].

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Source labels openErdős Problems · Number theory

Erdős Problem 389

Is it true that for every n1n \geq 1 there is a kk such that

n(n+1)(n+k1)(n+k)(n+2k1)? n(n + 1) \cdots (n + k - 1) \mid (n + k) \cdots (n + 2k - 1)?
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Source labels openErdős Problems · Number theory

Erdős Problem 39

Is there an infinite Sidon set ANA\subset \mathbb{N} such that A{1,N}ϵN1/2ϵ\lvert A\cap \{1\ldots,N\}\rvert \gg_\epsilon N^{1/2-\epsilon} for all ε>0\varepsilon > 0?

Source checked Jul 26, 20261 pinned Lean statementInspect problem