# A153298 (b-file synthesized from sequence entry)
0 1
1 2
2 11
3 68
4 443
5 2974
6 20361
7 141356
8 991738
9 7015814
10 49967892
11 357896120
12 2575844046
13 18616823352
14 135051785186
15 982949932092
16 7175591019313
17 52524480778590
18 385429134781530
19 2834791998208500
20 20893844524709649