# A294464 (b-file synthesized from sequence entry)
0 1
1 1
2 2
3 12
4 36
5 300
6 2520
7 20160
8 75600
9 2192400
10 30996000
11 276091200
12 2165486400
13 19070251200
14 968042275200
15 41954552640000
16 190974944160000
17 230641066656000
18 95607669148992000
19 -2052972258809472000
20 22839078791168640000
21 5074390517301705600000