Erdős problem 828
Is it true that, for any , there are infinitely many such that ?
Sources
FormalConjectures/ErdosProblems/
828.lean
Retained formal statement
When , Lehmer conjectured that if and only if is prime.
True ↔ ∀ n > 1, n.totient ∣ n - 1 ↔ Prime nOpenStatement only, no proof