This paper investigates the combinatorics that gives rise to the Boltzmann probability distribution. Despite being one of the most important distributions in physics and other fields of science, the mathematics of the underlying model of particles at different energy levels is underexplored. This paper gives a reconstruction, using multisets with fixed sums as mathematical representations. Counting (the coefficients of) such multisets gives a general description of binomial, trinomial, quadrinomial etc.\ coefficients, here called N-nomials. These coefficients give rise to multiple discrete Boltzmann distributions that are linked to explanations in the physics literature.