# A076124 (b-file synthesized from sequence entry)
1 1
2 4
3 12
4 36
5 180
6 1260
7 7560
8 25200
9 277200
10 1663200
11 21621600
12 64864800
13 735134400
14 6983776800
15 146659312800
16 1613252440800
17 37104806138400
18 445257673660800
19 4452576736608000
20 38588998383936000
21 1080491954750208000