# A121356 (b-file synthesized from sequence entry)
1 1
2 2
3 24
4 192
5 600
6 15840
7 211680
8 1612800
9 43545600
10 961632000
11 11416204800
12 365957222400
13 10766518963200
14 191617884057600
15 6758061133824000
16 254086360399872000
17 6058779650187264000
18 241382293453357056000