# A067897 (b-file synthesized from sequence entry)
0 0
1 0
2 0
3 0
4 2
5 8
6 32
7 112
8 412
9 1504
10 5760
11 22464
12 91224
13 379424
14 1632896
15 7201472
16 32709136
17 152094976
18 725810176
19 3540883968
20 17680145184
21 90115509888
22 469094763008
23 2489169367808
24 13465672180160
25 74161734785536