# A307526 (b-file synthesized from sequence entry)
0 1
1 4
2 24
3 144
4 828
5 4624
6 25296
7 136192
8 723160
9 3792564
10 19672240
11 101054512
12 514643952
13 2600665872
14 13049557280
15 65057605120
16 322413671228
17 1589046496704
18 7791836790504
19 38025622117168
20 184749163375664
21 893881787650016
22 4308024769339344
23 20685919693884672