# A084940 (b-file synthesized from sequence entry) 0 1 1 1 2 7 3 126 4 4284 5 235620 6 19085220 7 2137544640 8 316356606720 9 59791398670080 10 14050978687468800 11 4018579904616076800 12 1374354327378698265600 13 553864793933615401036800 14 259762588354865623086259200