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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 13 |
| 7 | 27 |
| 8 | 135 |
| 9 | 527 |
| 10 | 2581 |
| 11 | 17899 |
| 12 | 176183 |
| 13 | 1596080 |
| 14 | 23232289 |
| 15 | 321756402 |
| 16 | 6986541337 |
| 17 | 150961652645 |
| 18 | 4812704574943 |
| 19 | 154830665386988 |
[1,1,1,1,1,13,27,135,527,2581,17899,176183, 1596080,23232289,321756402,6986541337, 150961652645,4812704574943,154830665386988] |