# A223027 (b-file synthesized from sequence entry)
0 1
1 2
2 -2
3 4
4 -8
5 24
6 -72
7 224
8 -720
9 2370
10 -7940
11 27020
12 -93128
13 324424
14 -1140512
15 4041024
16 -14416030
17 51737020
18 -186663414
19 676656868
20 -2463300660
21 9001715448
22 -33009329056
23 121427520528
24 -447970371792
25 1657029908094
26 -6144260440620
27 22834249359960
28 -85037438715936