This is the definitive closure of the Beaver Emergence Model. After detailed analysis and observing the BBchallenge community’s work, the author concludes that BB(n) is fundamentally a "needle-in-a-haystack" combinatorial search rather than something solvable by elegant prime-density formulas. The earlier proposed value for BB(6) is refuted both structurally and numerically. This research thread is now closed.
Nicolas Antony Brown (Tue,) studied this question.