Muthoka, GeoffreyKamuti, IreriKimani, PatrickHussein, Lao2024-06-062024-06-062016-04ISSN (Online): 2319-7064http://repository.embuni.ac.ke/handle/embuni/4345ArticleThe cycle index of dihedral group Dn acting on the set of the vertices of a regular n-gon was studied by Harary and Palmer in 1973 [1]. Since then a number of researchers have studied the cycle indices dihedral group acting on different sets X={1,2,...,n} and the resulting formulas Dn have found applications in enumeration of a number of items. Muthoka (2015) [2] studied the cycle index formula of the –the n vertices of a regular -gon. In this paper we study the dihedral group acting on unordered pairs from the set X={1,2,..,n} cycle index formulas of acting on ordered pairs from the set . In each case the actions of the cyclic part and the reflection part are studied separately for both an even value of and an odd value of n .enCycle indexCycle typeMonomialArticle