Number theory MOC Falling factorial The falling factorial is a generalization of the factorial. In Knuth’s notation num 𝑥𝑛――=𝑛−1∏𝑘=0(𝑥−𝑘)=𝑥(𝑥−1)(𝑥−2)⋯(𝑥−𝑛+1) develop | en | SemBr