# A143420 (b-file synthesized from sequence entry)
2 1
3 8
4 55
5 370
6 2520
7 17472
8 123151
9 880070
10 6360706
11 46402312
12 341153384
13 2524722928
14 18789734496
15 140521154048
16 1055383259791
17 7956220907758
18 60179579570382
19 456545145078408
20 3472804505717170