# A259435 (b-file synthesized from sequence entry)
0 2
1 0
2 450
3 81920
4 2077650
5 22413312
6 148531250
7 716636160
8 2763575010
9 9017753600
10 25850353122
11 66816000000
12 158678718770
13 351151718400
14 731985584850
15 1449526034432
16 2745436781250
17 5000952545280
18 8800799033090
19 15019798118400
20 24938174692242
21 40392704000000