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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 25 |
| 5 | 197 |
| 6 | 1531 |
| 7 | 31791 |
| 8 | 876801 |
| 9 | 39890653 |
| 10 | 2918403939 |
| 11 | 324467879601 |
[1,1,1,25,197,1531,31791,876801,39890653, 2918403939,324467879601] |