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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 1 |
| 6 | 24 |
| 7 | 5 |
| 8 | 720 |
| 9 | 126 |
| 10 | 4480 |
| 11 | 6048 |
| 12 | 3628800 |
| 13 | 95040 |
| 14 | 479001600 |
| 15 | 55598400 |
| 16 | 5806080 |
| 17 | 1816214400 |
| 18 | 20922789888000 |
| 19 | 40327372800 |
| 20 | 6402373705728000 |
| 21 | 2501955993600 |
| 22 | 8911728967680000 |
| 23 | 193526296104960000 |
| 24 | 1124000727777607680000 |
| 25 | 696294353018880000 |
| 26 | 2256176006302688870400 |
[1,1,2,1,24,5,720,126,4480,6048,3628800,95040, 479001600,55598400,5806080,1816214400, 20922789888000,40327372800,6402373705728000, 2501955993600,8911728967680000,193526296104960000, 1124000727777607680000,696294353018880000, 2256176006302688870400] |