Exact, composite ternary nearest-neighbor degeneracies
Jeffrey L. Hock, Richmond B. McQuistan · Journal of Mathematical Physics · 1993
Closed-form expressions are developed that describe exactly the composite ternary nearest-neighbor degeneracies that arise when three different types of simple, indistinguishable particles are distributed on a one-dimensional lattice space to form prescribed numbers of the six possible kinds of nearest-neighbor pairs: (1–1), (1–2), (1–3), (2–2), (2–3), and (3–3).