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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 3 |
| 5 | 6 |
| 6 | 27 |
| 7 | 99 |
| 8 | 463 |
| 9 | 2233 |
| 10 | 11875 |
| 11 | 66925 |
| 12 | 402364 |
| 13 | 2555606 |
| 14 | 17115329 |
| 15 | 120368115 |
| 16 | 886510373 |
| 17 | 6819231506 |
[1,1,1,3,6,27,99,463,2233,11875,66925,402364, 2555606,17115329,120368115,886510373,6819231506] |