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Erdős problem 469

Does the sum of the reciprocals of all primitive pseudoperfect numbers converge?

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2 retained statements36c6d0fef71a

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FormalConjectures/ErdosProblems/

469.lean

Retained formal statement1 of 1

Let AA be the set of all nn such that n=d1+⋯+dkn = d_1 + ⋯ + d_k with did_i distinct proper divisors of nn, but this is not true for any m∣nm ∣ n with m<nm < n. Does: ∑n∈A1n \sum_{n ∈ A} \frac 1 n converge?

Yes: the sum converges. This was proved by Lewis [Le25], whose proof has been formalized in Lean.

FormalConjectures/ErdosProblems/469.leanErdos469.erdos_4691 lineExact file
True ↔ Summable fun n => 1 / ↑↑n
SolvedProof has a holelean4external proof

The proof uses `sorry`: part of the argument is written but not proved. Lean accepts the file; it does not accept the theorem.