# A066397 (b-file synthesized from sequence entry)
0 1
1 -2
2 6
3 -20
4 50
5 168
6 -4732
7 54024
8 -356670
9 -1558040
10 106069172
11 -2197188864
12 26605890220
13 22266781600
14 -12120090377400
15 402165029201744
16 -7732409047854318
17 38209542402620232
18 4126723132306766900
19 -211906442415502467360
20 5955735723962955009156