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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 7 |
| 2 | 137 |
| 3 | 5535 |
| 4 | 386481 |
| 5 | 41604055 |
| 6 | 6390472441 |
| 7 | 1326107352879 |
| 8 | 357130810766305 |
| 9 | 121056393177867303 |
| 10 | 50420813008501457897 |
| 11 | 25307979564532627724095 |
| 12 | 15065045963101006722139793 |
[1,7,137,5535,386481,41604055,6390472441, 1326107352879,357130810766305,121056393177867303, 50420813008501457897,25307979564532627724095, 15065045963101006722139793] |