# A137957 (b-file synthesized from sequence entry)
0 1
1 1
2 3
3 15
4 79
5 468
6 2895
7 18670
8 123765
9 838860
10 5785503
11 40473729
12 286504086
13 2048388112
14 14770313397
15 107290913232
16 784380664232
17 5766985753620
18 42614014459911
19 316304429143995
20 2357275139670183
21 17631888703154172