Erdős problem 399
Is it true that there are no solutions to n! = x^k ± y^k with x,y,n ∈ ℕ, x*y > 1, and k > 2?
Sources
FormalConjectures/ErdosProblems/
399.lean
Retained formal statement
Cambie has also observed that considerations modulo rule out any solutions to with and .
∀ {n x y : ℕ}, x.Coprime y → 1 < x * y → n.factorial ≠ x ^ 4 + y ^ 4SolvedStatement only, no proof