# A025608 (b-file synthesized from sequence entry)
0 0
1 0
2 2
3 36
4 560
5 8160
6 116192
7 1638336
8 23006720
9 322513920
10 4517714432
11 63263118336
12 885774356480
13 12401385185280
14 173622657769472
15 2430736799809536
16 34030432743587840
17 476426763687690240
18 6669978923292557312
19 93379730316084903936
20 1307316376765123788800