# A075358 (b-file synthesized from sequence entry)
1 1
2 3
3 20
4 30
5 336
6 5040
7 7920
8 154440
9 3603600
10 5765760
11 160392960
12 5079110400
13 8204716800
14 296541907200
15 11861676288000
16 520431047136000
17 857180548224000
18 41430393164160000
19 2163102632570880000
20 3569119343741952000