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Let $1\leq a_1<a_2<\cdots$ be a sequence of integers such that no $a_i$ is the sum of consecutive $a_j$ for $j<i$. Is it true that \[\limsup \frac{a_n}{n}=\infty?\] Or even \[\lim \frac{1}{\log x}\sum_{a_n<x}\frac{1}{a_n}=0?\]
It is easy to see that $\liminf a_n/n<\infty$ is possible.

See also [359].