2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/117760Let D be the circulant digraph with n vertices and connection set {2,3,c}. (Assume D is loopless and has outdegree 3.) Work of S.C.Locke and D.Witte implies that if n is a multiple of 6, c is either (n/2) + 2 or (n/2) + 3, and c is even, then D does not have a hamiltonian cycle. For all other cases, we construct a hamiltonian cycle in D.11 pages, no figuresCombinatorics05C45; 05C20, 05C25text