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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 13 |
| 6 | 57 |
| 7 | 273 |
| 8 | 2363 |
| 9 | 27689 |
| 10 | 439785 |
| 11 | 10940975 |
| 12 | 360992565 |
| 13 | 16603747977 |
| 14 | 1090432526531 |
[1,1,1,1,13,57,273,2363,27689,439785,10940975, 360992565,16603747977,1090432526531] |