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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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For $S(x) = \#\{(a,b) : a + b \le x,\ \sigma(a) + \sigma(b) = \sigma(a+b)\}$, is $S(x) \sim cx$? The preprint claims $S(x)$ grows faster than $x (\log x)^R$ for every fixed $R$, ruling out the linear asymptotic.

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