# A073973 (b-file synthesized from sequence entry)
1 0
2 2
3 6
4 24
5 180
6 1440
7 9072
8 50544
9 286416
10 1658880
11 9722592
12 58335552
13 356638464
14 2179768320
15 13180786560
16 79012495872
17 472093588224
18 2821539889152
19 16894457846784
20 101356447675392
21 608733733690368
22 3656096522698752
23 21947538146863104
24 131685228881178624