# A052614 (b-file synthesized from sequence entry) 0 1 1 1 2 2 3 6 4 48 5 240 6 1440 7 10080 8 120960 9 1088640 10 10886400 11 119750400 12 1916006400 13 24908083200 14 348713164800 15 5230697472000 16 104613949440000 17 1778437140480000 18 32011868528640000 19 608225502044160000