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| n | a(n) |
|---|---|
| 6 | 1 |
| 7 | 21 |
| 8 | 322 |
| 9 | 4284 |
| 10 | 52941 |
| 11 | 627627 |
| 12 | 7264499 |
| 13 | 82948008 |
| 14 | 940359420 |
| 15 | 10628025408 |
| 16 | 120071145376 |
| 17 | 1358324810752 |
| 18 | 15403850755456 |
| 19 | 175232115148032 |
| 20 | 2000450203866368 |
| 21 | 22922052379355136 |
| 22 | 263639657993643008 |
| 23 | 3043516686354636800 |
| 24 | 35260990780587196416 |
| 25 | 409914386080322027520 |
[1,21,322,4284,52941,627627,7264499,82948008, 940359420,10628025408,120071145376,1358324810752, 15403850755456,175232115148032,2000450203866368, 22922052379355136,263639657993643008, 3043516686354636800,35260990780587196416, 409914386080322027520] |