2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/71609Here we give two bijections, one to show that the number of UUU-free Dyck n-paths is the Motzkin number M_n, the other to obtain the (known) distributions of the parameters "number of UDUs" and "number of DDUs" on Dyck n-paths. The first bijection is straightforward, the second not quite so obvious.new title, generalized result, added references, 4 pagesCombinatorics05A15text