# A207874 (b-file synthesized from sequence entry)
1 2
2 16
3 72
4 400
5 1648
6 10742
7 51696
8 380632
9 2048344
10 17181610
11 99927528
12 1001175276
13 6019939360
14 76617072388
15 455429901920
16 7551993118538
17 45011858516784
18 1023575674079354
19 6041127787154280