# A353822 (b-file synthesized from sequence entry) 1 0 2 1 3 2 4 9 5 24 6 110 7 720 8 5985 9 39200 10 343224 11 3628800 12 41295870 13 479001600 14 6130959120 15 87104969952 16 1318070979225 17 20922789888000 18 354344089779680 19 6402373705728000 20 121882240625961816 21 2432849766865689600 22 51041049953430700800 23 1124000727777607680000