# A004371 (b-file synthesized from sequence entry)
3 1
4 28
5 595
6 11480
7 211876
8 3819816
9 67945521
10 1198774720
11 21042072975
12 368136785016
13 6426898010533
14 112044912118048
15 1951641934005400
16 33976189889821200
17 591315394579074378
18 10289781864706066800