# A166883 (b-file synthesized from sequence entry)
1 1
2 3
3 16
4 120
5 1200
6 15078
7 228984
8 4085028
9 83795085
10 1943920935
11 50333780640
12 1439208976920
13 45044270036220
14 1531759925038616
15 56239576979827360
16 2217379518189430404
17 93441321290076019236
18 4191262657895865499821