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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 9 |
| 5 | 41 |
| 6 | 209 |
| 7 | 1201 |
| 8 | 15001 |
| 9 | 432817 |
| 10 | 13376085 |
| 11 | 514375741 |
| 12 | 28401013633 |
[1,1,1,9,41,209,1201,15001,432817,13376085, 514375741,28401013633] |