# A027881 (b-file synthesized from sequence entry)
1 1
2 1
3 2
4 4
5 9
6 20
7 51
8 121
9 321
10 826
11 2186
12 5789
13 16114
14 42449
15 118281
16 328425
17 908933
18 2510553
19 7138324
20 19869748