# A032184 (b-file synthesized from sequence entry) 1 1 2 4 3 16 4 96 5 768 6 7680 7 92160 8 1290240 9 20643840 10 371589120 11 7431782400 12 163499212800 13 3923981107200 14 102023508787200 15 2856658246041600 16 85699747381248000 17 2742391916199936000 18 93241325150797824000 19 3356687705428721664000 20 127554132806291423232000