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Erdős problem 68

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∑n=2∞1n!−1=∑n=2∞∑k=1∞1(n!)k\sum_{n=2}^\infty \frac{1}{n!-1} = \sum_{n=2}^\infty \sum_{k=1}^\infty \frac{1}{(n!)^k}

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2 retained statements36c6d0fef71a

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FormalConjectures/ErdosProblems/

68.lean

Retained formal statement1 of 2

Is ∑n=2∞1n!−1\sum_{n=2}^\infty \frac{1}{n!-1} irrational?

FormalConjectures/ErdosProblems/68.leanErdos68.erdos_681 lineExact file
True ↔ Irrational (∑' (n : ℕ), 1 / (↑(n + 2).factorial - 1))
OpenStatement only, no proof