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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 5 |
| 6 | 21 |
| 7 | 57 |
| 8 | 285 |
| 9 | 1551 |
| 10 | 8309 |
| 11 | 69683 |
| 12 | 754867 |
| 13 | 9884801 |
| 14 | 158671845 |
| 15 | 3311072917 |
| 16 | 81046423259 |
[1,1,1,1,5,21,57,285,1551,8309,69683,754867, 9884801,158671845,3311072917,81046423259] |