# A155581 (b-file synthesized from sequence entry)
0 1
1 1
2 2
3 7
4 28
5 84
6 384
7 1824
8 6080
9 30400
10 304000
11 1064000
12 12768000
13 67488000
14 359936000
15 1934656000
16 30954496000
17 526226432000
18 2880397312000
19 15842185216000
20 316843704320000
21 1757042360320000
22 38654931927040000