On Hamiltonicity of circulant digraphs of outdegree three

This paper deals with Hamiltonicity of connected loopless circulant digraphs of outdegree three with connection set of the form { a , k a , c } , where k is an integer. In particular, we prove that if k = − 1 or k = 2 such a circulant digraph is Hamiltonian if and only if it is not isomorphic to the circulant digraph on 12 vertices with connection set { 3 , 6 , 4 } .