10944361domain: NAppears in sequencesA symmetrical triangle sequence: t(n,m)=n!*Eulerian[n + 1, m]^2 - n! + 1.at n=17A174692A symmetrical triangle sequence: t(n,m)=n!*Eulerian[n + 1, m]^2 - n! + 1.at n=18A174692