Polya counting formula

Polya counting formula

[¦pōl·yə ′kau̇n·tiŋ ‚fȯr·myə·lə]
(mathematics)
A formula which counts the number of functions from a finite set D to another finite set, with two functions ƒ and g assumed to be the same if some element of a fixed group of complete permutations of D takes ƒ into g.