# A356967 (b-file synthesized from sequence entry)
0 1
1 0
2 0
3 3
4 6
5 20
6 540
7 4284
8 35700
9 698760
10 10591560
11 155024100
12 3231336240
13 68704908480
14 1451024062488
15 35843008924800
16 950925111973200
17 25881184257364800
18 765471782499860160
19 24210772652940214320
20 797021694060934204800
21 27752674398657594805440