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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 6 |
| 6 | 48 |
| 7 | 1296 |
| 8 | 290304 |
| 9 | 1763596800 |
| 10 | 2400297571123200 |
| 11 | 19846204885558066176000000 |
| 12 | 223334408639880528216369404299444224000000 |
| 13 | 20780031060559302184531906881808103844643569442380668928000000000000 |
[1,1,1,2,6,48,1296,290304,1763596800, 2400297571123200,19846204885558066176000000, 223334408639880528216369404299444224000000, 20780031060559302184531906881808103844643569442380\ 668928000000000000] |