Published online by Cambridge University Press: 17 August 2018
We extend known results concerning crossing numbers by giving the crossingnumber of the join product $G+D_{n}$ , where the connected graph
$G$ consists of one
$4$ -cycle and of two leaves incident with the same vertex ofthe
$4$ -cycle, and
$D_{n}$ consists of
$n$ isolated vertices. The proofs are done with the help ofsoftware that generates all cyclic permutations for a given number
$k$ and creates a graph for calculating the distances betweenall
$(k-1)!$ vertices of the graph.
The research was supported by the internal faculty research project no. FEI-2017-39.