# A236958 (b-file synthesized from sequence entry)
0 1
1 1
2 2
3 16
4 104
5 1480
6 16640
7 337600
8 5432960
9 142650880
10 2996614400
11 96392704000
12 2502799769600
13 95198518604800
14 2946929024000000
15 129296981192704000
16 4651138853703680000
17 231108723265957888000
18 9477883333763366912000
19 525848755293052272640000
20 24223777158147502407680000