The Fibonacci numbers for the molecular graphs of linear phenylenes

Abstract

The concept of the Fibonacci number of an undirected graph G=(V,E) refers to the number of independent vertex subsets U of V such that no two vertices from U are adjacent in G. In this paper the Fibonacci numbers of molecular graphs corresponding to one type of phenylenes are calculated using the decomposition formula. Investigation of the Fibonacci numbers of certain classes of graphs leads to a difference equation or systems of difference equations. The explicit formula for the Fibonacci numbers of linear phenylenes is found as a function of the number n of hexagons in the phenylene.