# A221095 (b-file synthesized from sequence entry)
0 1
1 1
2 4
3 15
4 104
5 750
6 7254
7 74214
8 914528
9 12202632
10 183781080
11 2974435200
12 52965004872
13 1006137926040
14 20652503811744
15 449786292039000
16 10452618371303040
17 256326394027746240
18 6648055804021356864
19 181094856954089764032
20 5184169133931737988480