Enumerations of specific permutation classes

Enumerations of specific permutation classes refer to the systematic counting and characterization of permutations that belong to a defined class or family based on certain properties. A permutation is an arrangement of a set of elements, typically represented as a sequence. In combinatorial mathematics, particularly in the study of permutations, a permutation class is defined as a set of permutations that can be characterized by a restriction, such as avoiding certain "forbidden" permutations or following particular combinatorial patterns.