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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 18 |
| 2 | 324 |
| 3 | 5658 |
| 4 | 98766 |
| 5 | 1683597 |
| 6 | 28677387 |
| 7 | 479763588 |
| 8 | 8014917042 |
| 9 | 132060434889 |
| 10 | 2170519816231 |
[1,18,324,5658,98766,1683597,28677387,479763588, 8014917042,132060434889,2170519816231] |