# A105254 (b-file synthesized from sequence entry) 0 1 1 96 2 2808 3 43680 4 450450 5 3459456 6 21237216 7 109219968 8 486370170 9 1921462400 10 6859620768 11 22449667968 12 68128506264 13 193501082880 14 518306472000 15 1317650231040 16 3196331224515 17 7432299594720 18 16630917303000 19 35933837940000 20 75191555889450 21 152770145299200