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Erdős problem 448

Let τ(n)\tau(n) count the divisors of nn and τ+(n)\tau^+(n) count the number of kk such that nn has a divisor in [2k,2k+1)[2^k, 2^{k+1}). Is it true that, for all ϵ>0\epsilon > 0, τ+(n)<ϵ⋅τ(n) \tau^+(n) < \epsilon \cdot \tau(n) for almost all nn?

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The source's own material, retained exactly.

8 retained statements36c6d0fef71a

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FormalConjectures/ErdosProblems/

448.lean

Retained formal statement6 of 8

Always τ+(n)≤τ(n)\tau^+(n) \le \tau(n): the occupied dyadic blocks are the image of the divisor set under Nat.log 2, and an image has at most as many elements as its source. This is what makes the ϵ<1\epsilon < 1 comparison in the problem meaningful.

FormalConjectures/ErdosProblems/448.leanErdos448.tauPlus_le_tau1 lineExact file
∀ (n : ℕ), Erdos448.tauPlus n ≤ n.divisors.card
TestStatement only, no proof