Topological indices computing on random chain structures

Topological indices are a vital tool in QSAR/QSPR study, and Randic index and Zagreb index are mostly historical and well-known indices which have been widely used to predict the properties of compounds. In recent years, to meet the demands from various engineering applications, some variants of Randic index and Zagreb index are defined and investigated. In this work, we determine the redefined Zagreb indices, forgotten index, reduced reciprocal Randic index and reduced second Zagreb index for random polyphenyl chain and random spiro chain which are produced by zeroth-order Markov process and frequently appears in the field of materials and pharmacology. Furthermore, the average values and special settings in p(1) or p(2) to be zero are discussed.