# A321521 (b-file synthesized from sequence entry)
1 1
2 1
3 7
4 21
5 121
6 715
7 5041
8 40293
9 362887
10 3628681
11 39916801
12 479000895
13 6227020801
14 87178286161
15 1307674368127
16 20922789847653
17 355687428096001
18 6402373705365835
19 121645100408832001
20 2432902008173011101
21 51090942171709445047
22 1124000727777567763201