# A001277 (b-file synthesized from sequence entry)
2 1
3 3
4 12
5 56
6 321
7 2175
8 17008
9 150504
10 1485465
11 16170035
12 192384876
13 2483177808
14 34554278857
15 515620794591
16 8212685046336
17 139062777326000
18 2494364438359953
19 47245095998005059
20 942259727190907180
21 19737566982241851720
22 433234326593362631601
23 9943659797649140568863