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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 28 |
| 4 | 504 |
| 5 | 26520 |
| 6 | 3090528 |
| 7 | 690908400 |
| 8 | 432222336000 |
| 9 | 543025101265920 |
| 10 | 1255553120600064000 |
| 11 | 6002949274226395545600 |
| 12 | 65900815978203369461760000 |
| 13 | 1290586365875976383280969154560 |
| 14 | 48847915039427778415352397535641600 |
[1,3,28,504,26520,3090528,690908400,432222336000, 543025101265920,1255553120600064000, 6002949274226395545600,65900815978203369461760000, 1290586365875976383280969154560, 48847915039427778415352397535641600] |