# A230056 (b-file synthesized from sequence entry)
0 1
1 4
2 9
3 30
4 132
5 720
6 4680
7 35280
8 302400
9 2903040
10 30844800
11 359251200
12 4550515200
13 62270208000
14 915372057600
15 14384418048000
16 240612083712000
17 4268249137152000
18 80029671321600000
19 1581386305314816000
20 32844177110384640000
21 715273190403932160000
22 16298010552775311360000