# A206855 (b-file synthesized from sequence entry)
0 0
1 0
2 2
3 12
4 96
5 1000
6 12960
7 201684
8 3670016
9 76527504
10 1800000000
11 47158953820
12 1362182012928
13 43011849456888
14 1474041721757696
15 54493461914062500
16 2161727821137838080
17 91597537648314105376
18 4128944057284204560384
19 197293926880252878693804
20 9961472000000000000000000