# A019988 (b-file synthesized from sequence entry)
1 1
2 2
3 5
4 16
5 55
6 222
7 950
8 4265
9 19591
10 91678
11 434005
12 2073783
13 9979772
14 48315186
15 235088794
16 1148891118
17 5636168859
18 27743309673