# A374860 (b-file synthesized from sequence entry)
0 1
1 2
2 8
3 40
4 280
5 2520
6 25200
7 302400
8 3931200
9 58968000
10 1002456000
11 18044208000
12 360884160000
13 7939451520000
14 182607384960000
15 4565184624000000
16 118694800224000000
17 3323454406272000000
18 99703632188160000000
19 3090812597832960000000
20 101996815728487680000000