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| n | a(n) |
|---|---|
| 4 | 1 |
| 5 | 12 |
| 6 | 119 |
| 7 | 1177 |
| 8 | 12217 |
| 9 | 135302 |
| 10 | 1606446 |
| 11 | 20450052 |
| 12 | 278604252 |
| 13 | 4051377504 |
| 14 | 62702222112 |
| 15 | 1029832270848 |
| 16 | 17899305402240 |
| 17 | 328353314855040 |
| 18 | 6341705227082880 |
| 19 | 128655706986282240 |
| 20 | 2735782096305749760 |
| 21 | 60855815849067648000 |
| 22 | 1413487524282196608000 |
[1,12,119,1177,12217,135302,1606446,20450052, 278604252,4051377504,62702222112,1029832270848, 17899305402240,328353314855040,6341705227082880, 128655706986282240,2735782096305749760, 60855815849067648000,1413487524282196608000] |