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| n | a(n) |
|---|---|
| 2 | 4 |
| 3 | 432 |
| 4 | 2592 |
| 5 | 139968 |
| 6 | 139968 |
| 7 | 174960000000 |
| 8 | 56358560858112 |
| 9 | 84537841287168 |
| 10 | 578415690713088 |
| 11 | 578415690713088 |
| 12 | 1141260857376768 |
| 13 | 61628086298345472 |
| 14 | 61628086298345472 |
| 15 | 61628086298345472 |
| 16 | 322850407500000000000000000000 |
| 17 | 322850407500000000000000000000 |
| 18 | 62518864539857068333550694039552 |
[4,432,2592,139968,139968,174960000000, 56358560858112,84537841287168,578415690713088, 578415690713088,1141260857376768, 61628086298345472,61628086298345472, 61628086298345472,322850407500000000000000000000, 322850407500000000000000000000, 62518864539857068333550694039552] |