# A001759 (b-file synthesized from sequence entry)
4 2
5 28
6 236
7 1852
8 14622
9 119964
10 1034992
11 9434444
12 90968602
13 927367340
14 9982234068
15 113261721276
16 1352111669942
17 16950982295356
18 222752212005464
19 3062768908594348
20 43987314357078642
21 658804420084315212