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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 3 |
| 2 | 2 |
| 3 | 18 |
| 4 | 98 |
| 5 | 33282 |
| 6 | 319994402 |
| 7 | 354455304050635218 |
| 8 | 36294953231792713902640647988908098 |
[0,3,2,18,98,33282,319994402,354455304050635218, 36294953231792713902640647988908098] |