Infinitely many composites n with φ⁺(n) dividing n−1
Determine whether there exist infinitely many positive composite integers n such that φ⁺(n) divides n−1, where φ⁺(n)=∏_{p\mid n}(φ(p^{v_p(n)})+1).
References
Open question 5: Are there infinitely many positive composite integers $n$ such that $\varphi+(n)\mid (n-1)$?
— Divisibility and Sequence Properties of $σ^+$ and $\varphi^+$
(2508.11660 - Mandal, 6 Aug 2025) in Section 2, Main Results (Open question 5)