# A138912 (b-file synthesized from sequence entry)
0 1
1 1
2 2
3 9
4 28
5 145
6 726
7 4249
8 27000
9 186561
10 1387450
11 11034001
12 93295236
13 834720913
14 7870851366
15 77943848025
16 808159323376
17 8749874083585
18 98687599614450
19 1157060036429857
20 14075106913366140
21 177337182574590801