# A063888 (b-file synthesized from sequence entry)
0 1
1 6
2 30
3 180
4 1026
5 6156
6 35940
7 215640
8 1271106
9 7626636
10 45182124
11 271092744
12 1610875836
13 9665255016
14 57546367704
15 345278206224
16 2058613385346
17 12351680312076
18 73717606430364
19 442305638582184
20 2641804748619732