# A136591 (b-file synthesized from sequence entry)
1 1
2 1
3 -4
4 6
5 24
6 -240
7 720
8 5040
9 -80640
10 362880
11 3628800
12 -79833600
13 479001600
14 6227020800
15 -174356582400
16 1307674368000
17 20922789888000
18 -711374856192000
19 6402373705728000
20 121645100408832000
21 -4865804016353280000
22 51090942171709440000