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Erdős problem 1061

Let S(x)S(x) count ordered pairs (a,b)(a,b) with a+b≤xa+b \le x and σ(a)+σ(b)=σ(a+b)\sigma(a)+\sigma(b) = \sigma(a+b). Erdos asked whether S(x)∼cxS(x) \sim cx. The opposite extreme holds: for every R>0R > 0, S(x)/(x(log⁡x)R)→∞S(x)/(x(\log x)^R) \to \infty, so the count beats every fixed logarithmic scale.

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FormalConjectures/ErdosProblems/

1061.lean

Retained formal statement1 of 1

How many (ordered) solutions are there to σ(a) + σ(b) = σ(a + b) with a + b ≤ x? Is it true that this number is asymptotic to c * x for some constant c > 0?

FormalConjectures/ErdosProblems/1061.leanErdos1061.erdos_10611 lineExact file
True ↔ ∃ c, 0 < c ∧ Asymptotics.IsEquivalent Filter.atTop Erdos1061.S fun x => c * x
OpenStatement only, no proof