Skip to content

Erdős problem 377

Is there some absolute constant C>0C > 0 such that ∑p≤n1p∤(2nn)1p≤C \sum_{p \leq n} 1_{p\nmid {2n \choose n}}\frac{1}{p} \leq C for all nn?

Sources

The source's own material, retained exactly.

5 retained statements36c6d0fef71a

Open selected source

FormalConjectures/ErdosProblems/

377.lean

Retained formal statement5 of 5

Erdos, Graham, Ruzsa, and Straus proved that if f(n)=∑p≤n1p∤(2nn)1p f(n) = \sum_{p \leq n} 1_{p\nmid {2n \choose n}}\frac{1}{p} then there is some constant c<1c < 1 such that for all large nn f(n)≤clog⁡log⁡n. f(n) \leq c \log\log n.

[EGRS75] Erdős, P. and Graham, R. L. and Ruzsa, I. Z. and Straus, E. G., _On the prime factors of (2nn)\binom{2n}{n}_. Math. Comp. (1975), 83-92.

FormalConjectures/ErdosProblems/377.leanErdos377.erdos_377.variants.ub1 lineExact file
∃ c < 1, ∀ᶠ (n : ℕ) in Filter.atTop, Erdos377.sumInvPrimesNotDvdCentralBinom n ≤ c * Real.log (Real.log ↑n)
SolvedStatement only, no proof