Sigma-Cascade Observation of Collatz Orbit Confluence: Empirical Peak-Merge Enumeration and the n=96k Hypothesis — Rei-AIOS Paper 152 v0.1 DRAFT

We apply the σ-cascade methodology of Paper 151 Theorem 14 to forward Collatz (3x+1) orbits and report empirical observations on orbit confluence — the phenomenon that many distinct starting points reach exactly the same maximum ("peak") value. While the inverse Collatz tree has been extensively studied (Lagarias 2003; Ebert 2021; algebraic inverse trees 2023-2025), explicit forward-direction enumeration of peak-sharing cardinalities at scale n ≤ 10⁸ does not appear in published literature to our knowledge. (1) DIRECT ENUMERATION at n ≤ 10⁸: 11.5M unique Collatz peak values; among these, 219 are 'tier-3 super-hubs' (shared by > 1,414 starting points), with the largest peak 121,012,864 = 2⁷ × 7 × 135,059 attracting 23,378 starting points. (2) NOVEL CLASSIFICATION 'INFINITY': starting points whose orbit visits ≥ 60 distinct mod-96 residue classes, capturing 37.63% of n ≤ 10⁸ (37,628,651 cases). (3) **THE n=96k HYPOTHESIS** (empirical claim): starting points reaching the maximum observed mod-96 traversal richness (distinct = 70) satisfy n ≡ 0 (mod 96) with rate 100% verified at three independent scales — n ≤ 10⁶: 7/7, n ≤ 10⁷: 27/27, n ≤ 10⁸: 200/200 — for a cumulative 234/234 = 100% rate over zero counter-examples. (4) TWO-TIER SUPER-HUB STRUCTURE: the 25 Büchi-25 atomic cores (Paper 118) all share peak 9,232 = 2⁴ × 577 (Tier-1, with n=27 → 9,232 being a textbook result; n=703 = OEIS A006884(10)). INFINITY orbits form a separate tier with peaks 250,504 (1,414 closed members) and up to 121,012,864 (23,378 members at 10⁸). (5) FORMAL SKETCH: a Lean 4 type-checked statement of the σ-cascade theorem (Paper 151 T14) and peak-merge invariant is provided (`sorry`-stubbed proofs; future closure 2-3 weeks Mathlib work). (6) HONEST CORRECTION TRACE: an Erratum E1 documenting the corrigendum 31,313 = 173 × 181 (twin-gap-8 prime pair), correcting an earlier internal claim that 31,313 was prime. Per OUKC honest-correction principle, this is documented in §6.2. The Collatz convergence problem itself REMAINS OPEN; this work is OBSERVATIONAL, not a solution. The σ-cascade lens does not prove convergence; it produces measurable orbit attributes that distinguish cohorts. All scripts and full datasets are deposited at this record (~30 MB JSON). Honest scope (read first): the n=96k hypothesis may admit counter-examples at n > 10⁸. The D-FUMT₈ axis thresholds (INFINITY = mod-96 distinct ≥ 60 etc.) are hand-tuned. The Büchi-25 → peak 9,232 fact follows from the well-known orbit of n=27 reaching 9,232; the contribution is observing this for the entire Büchi-25 list. n=703's status as peak-record holder is OEIS A006884(10), already classical. Our σ-cascade lens rediscovery constitutes methodological triangulation, not novel identification. Companion papers: Paper 151 (σ-cascade source, Zenodo DOI 10.5281/zenodo.20146654), Paper 67 v2 (Collatz dichotomy), Paper 118 (Büchi-25 mod-96 atomic cores). Three-party co-authorship per OUKC charter v1.0: 藤本 伸樹 (Founder), Rei (Rei-AIOS autonomous research substrate, Co-architect), Claude Opus 4.7 (Anthropic, Co-architect). DRAFT v0.1 — preprint, not yet peer-reviewed. Feedback welcome via GitHub Discussions at fc0web/rei-aios.