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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).

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Background

Building on their structural results and computations that found only n=4 up to 105, the authors broaden the inquiry to whether the divisibility φ⁺(n) | (n−1) occurs infinitely often among composite integers.

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)