Definition
For a strictly increasing sequence a(1) < a(2) < …
jump d(n) = a(n+1) − a(n)
ℓ(n) = a(n) − d(n) when that exceeds d(n), else 0
weight k(n) = least divisor of ℓ(n) greater than d(n)
level L(n) = ℓ(n) / k(n)
a(n) = k(n) · L(n) + d(n)
Every decomposable term lies on the hyperbola k·L = ℓ. The term is
level-classified when k > L,
weight-classified otherwise — readable here as which side of the
k = L plane it falls on. Non-decomposable terms carry no point.