# A374497 (b-file synthesized from sequence entry)
0 1
1 6
2 36
3 200
4 1080
5 5712
6 29792
7 153792
8 787680
9 4009280
10 20304768
11 102405888
12 514678528
13 2579028480
14 12890311680
15 64283809792
16 319954540032
17 1589720712192
18 7886437652480
19 39069462835200
20 193307835764736
21 955361266917376
22 4716674314223616
23 23264437702656000