# A013229 (b-file synthesized from sequence entry)
0 0
1 0
2 -1
3 1
4 -6
5 15
6 -90
7 285
8 -1960
9 2275
10 -12600
11 -877725
12 9088200
13 -206895975
14 2291088800
15 -43975670375
16 519884196000
17 -10108488755625
18 124295092272000
19 -2588043770222625
20 31717643136725000