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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 12 |
| 4 | 140 |
| 5 | 3020 |
| 6 | 100362 |
| 7 | 4768624 |
| 8 | 305498328 |
| 9 | 25293331098 |
| 10 | 2619996058190 |
[1,2,12,140,3020,100362,4768624,305498328, 25293331098,2619996058190] |