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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 19 |
| 3 | 2265 |
| 4 | 1130500 |
| 5 | 1023558900 |
| 6 | 2110942716750 |
| 7 | 8930744592735000 |
[1,19,2265,1130500,1023558900,2110942716750, 8930744592735000] |