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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 90 |
| 4 | 97200 |
| 5 | 14276736000 |
| 6 | 1107198567383040000 |
| 7 | 178601637561927097909248000000 |
| 8 | 237856509917156074017606774172522905600000000 |
| 9 | 10420480393274493153643458442091600404477248333907230720000000000 |
[1,3,90,97200,14276736000,1107198567383040000, 178601637561927097909248000000, 237856509917156074017606774172522905600000000, 10420480393274493153643458442091600404477248333907\ 230720000000000] |