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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 25 |
| 6 | 149 |
| 7 | 649 |
| 8 | 7345 |
| 9 | 81717 |
| 10 | 923853 |
| 11 | 27725125 |
| 12 | 920411959 |
| 13 | 33783967463 |
[1,1,1,1,25,149,649,7345,81717,923853,27725125, 920411959,33783967463] |