# A001415 (b-file synthesized from sequence entry)
0 1
1 2
2 8
3 60
4 320
5 1980
6 10512
7 60788
8 320896
9 1787904
10 9381840
11 51081844
12 266680992
13 1429703548
14 7432424160
15 39409195740
16 204150606976
17 1073644675448
18 5545305620064