The Reduced 6k+_1(2)/5 Collatz-Type Domain with Three Observed Attractors up to 10^11

This record presents an exhaustive computational study of the reduced 6k+_1(2)/5 Collatz-type domain on positive integers not divisible by 5. The residue-dependent map removes all factors of 5 after applying the appropriate affine transformation and exhibits three observed terminal attractors: the fixed points represented by 1 and 2, and a 9-cycle. An exhaustive 128-bit computation tested all 80,000,000,000 positive starting values not divisible by 5 up to 10^11. Every tested orbit entered one of the three known attractors. No additional cycles were detected, no 128-bit overflow occurred, and no trajectory reached the imposed step limit. At the full cutoff, the observed basin proportions were approximately 51.49947907% for the attractor at 1, 14.51658518% for the attractor at 2, and 33.98393574% for the 9-cycle. The maximum observed stopping time was 755 steps, attained at n = 63,909,268,656. The largest observed trajectory peak was 18,774,256,269,070,896,812,821, attained on the orbit starting at n = 73,433,001,822. The accompanying article develops the algebraic structure of the map and its periodic orbits, numerical examples for all three observed attractors, a five-adic probabilistic contraction model, inverse-branch and basin interpretations, and a clear distinction between finite exhaustive verification and global conjecture. The computational package contains the verified v2 C source code, complete production-run data, chunk summaries, record data, final summary, reproducibility documentation, SHA-256 checksums, and the LaTeX source of the article. The exhaustive finite computation provides strong computational evidence for the observed three-attractor structure up to 10^11, but it is not claimed as a proof of global convergence or of the absence of additional attractors beyond the verified range.