# A003211 (b-file synthesized from sequence entry)
0 1
1 6
2 30
3 114
4 438
5 1542
6 5754
7 19574
8 71958
9 233574
10 870666
11 2696274
12 10375770
13 30198116
14 122634404
15 327024444
16 1460721616
17 3347244554
18 17795165832