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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 1 |
| 7 | 3 |
| 8 | 17 |
| 9 | 41 |
| 10 | 79 |
| 11 | 223 |
| 12 | 801 |
| 13 | 2615 |
| 14 | 9741 |
| 15 | 48585 |
| 16 | 263431 |
| 17 | 1569087 |
| 18 | 9472069 |
| 19 | 65995437 |
| 20 | 509339343 |
| 21 | 4406836165 |
[1,1,1,1,1,1,3,17,41,79,223,801,2615,9741,48585, 263431,1569087,9472069,65995437,509339343, 4406836165] |