Flory–Schulz distribution
The Flory–Schulz distribution is a discrete probability distribution named after Paul Flory and Günter Victor Schulz that describes the relative ratios of polymers of different length that occur in an ideal step-growth polymerization process. The probability mass function (pmf) for the mass fraction of chains of length k {\displaystyle k} is: w a ( k ) = a 2 k ( 1 − a ) k − 1 .
Source: Wikipedia — Flory–Schulz distribution (CC BY-SA 4.0)