Formula Development (Descent Portion)

-- starting from e.g. {5[8]} divide into 3 subsets == {(0[3]}, {1[3]}, and {2[3]}

-- {5[8]} is completely composed of {5[24]},{13[24]}, and {21[24]}

-- in general, {c[d]} becomes {c[3d]}, {(c+d)[3d]}, and {(c+2d)[3d]}

-- only c of c[d] determines the next step (because 3d[3] is 0)

-- whence {5[24]} gives s-step predecessors; {13[24]} gives b-step predecessors; {21[24]} is a leaf set

-- apply this same process to each subset to generate successive predecessor sets

-- examine a table which goes 3 levels deep