# A121517 (b-file synthesized from sequence entry)
0 1
1 1
2 7
3 31
4 151
5 721
6 3457
7 16561
8 79351
9 380191
10 1821607
11 8727841
12 41817601
13 200360161
14 959983207
15 4599555871
16 22037796151
17 105589424881
18 505909328257
19 2423957216401
20 11613876753751
21 55645426552351
22 266613256008007