# A006213 (b-file synthesized from sequence entry)
0 0
1 2
2 10
3 46
4 224
5 1202
6 7120
7 46366
8 329984
9 2551202
10 21306880
11 191252686
12 1836652544
13 18793429202
14 204154071040
15 2346705139006
16 28459289083904
17 363156549211202
18 4864231397785600
19 68237760828425326
20 1000569392347480064
21 15306487540377673202