Erdős problem 1049
Let be a rational number. Is irrational, where counts the divisors of ?
Sources
FormalConjectures/ErdosProblems/
1049.lean
Retained formal statement
Erdős [Er48] proved that this is true if is an integer.
∀ t ≥ 2, Irrational (∑' (n : ℕ+), 1 / (↑t ^ ↑n - 1))SolvedStatement only, no proof