# A121257 (b-file synthesized from sequence entry)
1 4
2 20
3 76
4 260
5 840
6 2616
7 7940
8 23644
9 69380
10 201220
11 578064
12 1647600
13 4664836
14 13132580
15 36789820
16 102621956
17 285174360
18 789810984
19 2180889860
20 6005842540
21 16498958324
22 45225010180
23 123715684896
24 337806904800
25 920819997700