2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/74580We calculate the action of some Hecke operators on spaces of modular forms spanned by the Siegel theta-series of certain genera of strongly modular lattices closely related to the Leech lattice. Their eigenforms provide explicit examples of Siegel cusp forms.Number Theory11F46, 11H06text