The crossing number of K1,4,nK1,4,n

In this paper, we prove that the crossing number of the complete tripartite graph K1,4,nK1,4,n is n(n-1)n(n-1). Our result also shows that the crossing number of the Cartesian product S4□SnS4□Sn is n(n-1)n(n-1), where SnSn denotes the star K1,nK1,n for arbitrary integer n⩾1n⩾1.