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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 6 |
| 3 | 90 |
| 4 | 2484 |
| 5 | 109339 |
| 6 | 7019168 |
| 7 | 619051405 |
| 8 | 71824824028 |
| 9 | 10607707589930 |
| 10 | 1943225496142169 |
[1,6,90,2484,109339,7019168,619051405,71824824028, 10607707589930,1943225496142169] |