# A056271 (b-file synthesized from sequence entry)
1 0
2 0
3 0
4 0
5 0
6 720
7 15120
8 191520
9 1905120
10 16435440
11 129230640
12 953028720
13 6711344640
14 45674173440
15 302899156560
16 1969146930240
17 12604139926560
18 79694818842240
19 499018753280880
20 3100376788241040