# A111550 (b-file synthesized from sequence entry)
0 0
1 2
2 6
3 32
4 222
5 1824
6 17016
7 176112
8 1993392
9 24438960
10 322294896
11 4548010032
12 68385367152
13 1091838106800
14 18454096189296
15 329306074785072
16 6189015238217712
17 122232512688657840
18 2531600753529542256