# A009152 (b-file synthesized from sequence entry)
0 1
1 -1
2 2
3 -4
4 12
5 -36
6 128
7 -456
8 1872
9 -7888
10 37600
11 -184064
12 990784
13 -5444544
14 32333824
15 -195982208
16 1272660224
17 -8441139456
18 59527313920
19 -428299217920
20 3252626013184
21 -25165446157312
22 204354574172160
23 -1689266143553536