# A002851 (b-file synthesized from sequence entry)
0 1
1 0
2 1
3 2
4 5
5 19
6 85
7 509
8 4060
9 41301
10 510489
11 7319447
12 117940535
13 2094480864
14 40497138011
15 845480228069
16 18941522184590
17 453090162062723
18 11523392072541432
19 310467244165539782
20 8832736318937756165