# A073988 (b-file synthesized from sequence entry)
1 0
2 0
3 9
4 72
5 300
6 1296
7 7056
8 42336
9 262440
10 1658880
11 10349856
12 62355744
13 367960320
14 2173796352
15 12958657344
16 77787495936
17 468419708160
18 2821109907456
19 16960580969472
20 101763485816832
21 609954817881600
22 3656096522698752
23 21926115464435712
24 131557435432187904