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arXiv · 0911.2660

Maximum GCD Among Pairs of Random Integers

R. W. R. Darling·E. E. Pyle
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Abstract

Fix $\alpha >0$, and sample $N$ integers uniformly at random from $\{1,2,\ldots ,\lfloor e^{\alpha N}\rfloor \}$. Given $\eta >0$, the probability that the maximum of the pairwise GCDs lies between $N^{2-\eta }$ and $N^{2+\eta}$ converges to 1 as $N\to \infty $. More precise estimates are obtained. This is a Birthday Problem: two of the random integers are likely to share some prime factor of order $N^2/\log [N]$. The proof generalizes to any arithmetical semigroup where a suitable form of the Prime Number Theorem is valid.

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R. W. R. Darling, E. E. Pyle. 2009-11-13. Maximum GCD Among Pairs of Random Integers. https://arxiv.org/abs/0911.2660

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