# A009384 (b-file synthesized from sequence entry)
0 0
1 1
2 -1
3 -1
4 6
5 1
6 -72
7 -1
8 1904
9 1
10 -89344
11 -1
12 6445824
13 1
14 -660602880
15 -1
16 91175548928
17 1
18 -16301080281088
19 -1
20 3664597991424000
21 1
22 -1011727950085619712
23 -1
24 336514395583207178240
25 1
26 -132722531082033166286848
27 -1