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Erdős problem 830

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We say that a,b∈Na,b\in \mathbb{N} are an amicable pair if σ(a)=σ(b)=a+b\sigma(a)=\sigma(b)=a+b. If A(x)A(x) counts the number of amicable 1≤a≤b≤x1\leq a\leq b\leq x then one can show that A(x)≤xexp⁡(−(12+o(1))(log⁡xlog⁡log⁡x)1/2)A(x) \leq x \exp(-(\tfrac{1}{2}+o(1))(\log x\log\log x)^{1/2}).

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Problem row
sha256:d36ce59008ccb5b4d5636a3aab15c0a324d9ef686538eacd3ee6c1bb2314814a
Metadata
sha256:7c01c62738fc522c90e94fece5ecadf8d3ab4afce80c5b09da104232f8694428
Observation
sha256:9c8326e865b6017b103af7611c852a06776d81964979b8ab5a1b800cd550dff6
Content
sha256:c07367cb150aed7b60513510c7bda72398ca09f915fa4d85b64eadd743482e6a
Repository
sha256:a956b84c437202e5a02cc9e036a621bd14a302b34a75758115730bdbb77c52a4
Projection
sha256:a4a96441668a9f8b33afbcb3f696a2639f5fae145f36ddc063d7f67d5fb87ce8
Source commit
36c6d0fef71a3fec84d9dcd5eeca4e22e378f7cb
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