# A354315 (b-file synthesized from sequence entry) 0 1 1 0 2 2 3 6 4 56 5 480 6 5664 7 75600 8 1182208 9 20829312 10 410768640 11 8943010560 12 213187497984 13 5520777799680 14 154333888579584 15 4631752470159360 16 148523272512307200 17 5067610703150284800 18 183308248516478828544 19 7006773595450681589760 20 282194468488468121518080