# A002928 (b-file synthesized from sequence entry)
0 1
1 0
2 -2
3 -8
4 -34
5 -152
6 -714
7 -3472
8 -17318
9 -88048
10 -454378
11 -2373048
12 -12515634
13 -66551016
14 -356345666
15 -1919453984
16 -10392792766
17 -56527200992
18 -308691183938
19 -1691769619240
20 -9301374102034