# A012653 (b-file synthesized from sequence entry)
0 0
1 0
2 2
3 -3
4 0
5 -10
6 -80
7 1764
8 -7392
9 17856
10 -41792
11 -7382320
12 134784320
13 -1068379104
14 7660192384
15 35293839840
16 -4466084847616
17 93476460710912
18 -1176630882269184
19 10358160914068992
20 214589448557477888