# A194559 (b-file synthesized from sequence entry)
0 1
1 1
2 4
3 18
4 132
5 900
6 10560
7 96600
8 1500240
9 19066320
10 369714240
11 5359163040
12 147177898560
13 2443958637120
14 76298578836480
15 1621294897622400
16 58906376034105600
17 1309870975014201600
18 60357698670132864000
19 1469955465552513139200
20 74262907856067567436800