# A012318 (b-file synthesized from sequence entry)
0 0
1 1
2 2
3 6
4 32
5 240
6 2000
7 19656
8 221888
9 2846784
10 40430848
11 632914304
12 10802538496
13 199980939392
14 3985563555584
15 85138224664832
16 1939700554334208
17 46962544699670528
18 1203843275552612352