Number of spanning trees in corona product graph

Being an invariant of a graph, the number of spanning trees in a graph G is one of the most important problems at graph theory. We aimed to get an explicit formula counting this number in the corona product graph. In this paper, we studied the corona product of a planar graph and an outer planar graph, then we calculated the number of spanning trees in this product graph. Our research findings highlight the efficiency of combinatorial method, which allowed us to count this number in huge graph like corona product graph easily.