# A122693 (b-file synthesized from sequence entry)
0 0
1 2
2 4
3 32
4 128
5 1152
6 6912
7 73728
8 589824
9 7372800
10 73728000
11 1061683200
12 12740198400
13 208089907200
14 2913258700800
15 53271016243200
16 852336259891200
17 17259809262796800
18 310676566730342400
19 6903923705118720000
20 138078474102374400000
21 3341499073277460480000