n | a(n) |
---|---|
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 |
[2,1,9,40,132,1032,7824,51912,530712,5619456, 53529984,707802624,9591229440,119716185600, 1938416832000,32061464064000,496487584512000, 9509523337728000,185772505605120000, 3434389946233344000] |