# A343581 (b-file synthesized from sequence entry)
0 1
1 0
2 2
3 6
4 36
5 240
6 1200
7 12600
8 58800
9 846720
10 3810240
11 69854400
12 307359360
13 6849722880
14 29682132480
15 779155977600
16 3339239904000
17 100919250432000
18 428906814336000
19 14668613050291200
20 61934143990118400
21 2364758225077248000
22 9931984545324441600
23 418798681661180620800