Infinitely many composites n with n+1 dividing σ⁺(n)
Determine whether there exist infinitely many positive composite integers n such that n+1 divides σ⁺(n), where σ⁺(n)=∏_{p\mid n}(σ(p^{v_p(n)})+1).
References
Open question 3: Are there infinitely many positive composite integers $n$ such that $n+1\mid \sigma+(n)$?
— Divisibility and Sequence Properties of $σ^+$ and $\varphi^+$
(2508.11660 - Mandal, 6 Aug 2025) in Section 2, Main Results (Open question 3)