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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 2 |
| 4 | 7 |
| 5 | 28 |
| 6 | 124 |
| 7 | 588 |
| 8 | 2938 |
| 9 | 15266 |
| 10 | 81770 |
| 11 | 448698 |
| 12 | 2510813 |
| 13 | 14277838 |
| 14 | 82286365 |
| 15 | 479610362 |
| 16 | 2822332127 |
| 17 | 16745262798 |
[1,2,7,28,124,588,2938,15266,81770,448698,2510813, 14277838,82286365,479610362,2822332127, 16745262798] |