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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 1 |
| 7 | 4 |
| 8 | 5 |
| 9 | 13 |
| 10 | 19 |
| 11 | 43 |
| 12 | 57 |
| 13 | 239 |
| 14 | 521 |
| 15 | 2347 |
| 16 | 5442 |
| 17 | 24758 |
| 18 | 63173 |
| 19 | 355006 |
| 20 | 1139569 |
| 21 | 7776109 |
| 22 | 29105899 |
| 23 | 223723640 |
| 24 | 955226817 |
| 25 | 8533424348 |
[1,1,1,1,1,1,4,5,13,19,43,57,239,521,2347,5442, 24758,63173,355006,1139569,7776109,29105899, 223723640,955226817,8533424348] |