English

Frequency Ordered Ratio Families Arising from the Factorization of $p_{m-1}+1$

Number Theory 2026-05-28 v2

Abstract

We investigate a ratio sequence derived from the factorization of pm1+1p_{m-1} + 1, where pnp_n denotes the nnth prime. For each m3m \geq 3, write pm1+1=LmRmp_{m-1} + 1 = L_m R_m with LmL_m the largest prime factor. Restricting to those mm for which Lm>mL_m > m (equivalently, mA223881m \in \text{A223881}), we obtain a multiset of values RmR_m. Since pm1+1p_{m-1}+1 is even and Lm>3L_m > 3 is odd, all values of RmR_m are strictly even. Sorting the distinct RmR_m by decreasing frequency yields a new sequence beginning 2,6,4,8,10,12,14,162, 6, 4, 8, 10, 12, 14, 16 \dots. This article explains how this construction arises naturally from the structure of A223881, why the ``family'' phenomenon appears in plots of pm1+1p_{m-1} + 1, and how the frequency ordering of RmR_m captures the dominant families. Additionally, we propose a heuristic asymptotic model explaining the observed frequency ordering via classical results on primes in arithmetic progressions and support the model with numerical log-log analysis.

Keywords

Cite

@article{arxiv.2605.08256,
  title  = {Frequency Ordered Ratio Families Arising from the Factorization of $p_{m-1}+1$},
  author = {Alexander R Povolotsky},
  journal= {arXiv preprint arXiv:2605.08256},
  year   = {2026}
}