# A204432 (b-file synthesized from sequence entry)
1 2
2 1
3 9
4 40
5 132
6 1032
7 7824
8 51912
9 530712
10 5619456
11 53529984
12 707802624
13 9591229440
14 119716185600
15 1938416832000
16 32061464064000
17 496487584512000
18 9509523337728000
19 185772505605120000
20 3434389946233344000