the proof notes, §8.1 (ii): the column values colVal n p b through the residues
r₀ = n % p, s₀ = 5n % p, and the closed forms of Σ_b c_b and Σ_b c_b²
(the column multiset β+1 once, β+3 μ times, β−1 (s₀−μ) times, β+4 (r₀−μ) times, β
otherwise).
Real indicator [c < r].