# 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