# A055303 (b-file synthesized from sequence entry)
3 3
4 36
5 360
6 3600
7 37800
8 423360
9 5080320
10 65318400
11 898128000
12 13172544000
13 205491686400
14 3399953356800
15 59499183744000
16 1098446469120000
17 21341245685760000
18 435361411989504000
19 9305850181275648000
20 208013121699102720000
21 4853639506312396800000