2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/76894By practicing the philosophy of our beloved late master, Marco Schutzenberger, to whose memory this article is dedicated, we give an insightful bijective proof of the three-term recurrence satisfied by the Hipparchus-Schroeder numbers 1,1,3,11,45,197,903, ...Combinatoricstext