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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 3 |
| 5 | 9 |
| 6 | 27 |
| 7 | 119 |
| 8 | 633 |
| 9 | 3943 |
| 10 | 30791 |
| 11 | 332473 |
| 12 | 4676705 |
| 13 | 79725173 |
| 14 | 1817184081 |
| 15 | 50545874411 |
| 16 | 1811092006865 |
[1,1,1,3,9,27,119,633,3943,30791,332473,4676705, 79725173,1817184081,50545874411,1811092006865] |