English English Wikipedia has an article on:Delannoy numberWikipedia Etymology Named after French army officer and amateur mathematician Henri Delannoy. Noun Delannoy number (plural Delannoy numbers) (mathematics) The number of possible paths from the southwest corner (0, 0) of a rectangular grid to the northeast corner (m, n), using only single steps north, northeast, or east. Wikiwand - on Seamless Wikipedia browsing. On steroids.