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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 7 |
| 4 | 28 |
| 5 | 67 |
| 6 | 289 |
| 7 | 723 |
| 8 | 3185 |
| 9 | 8677 |
| 10 | 38580 |
| 11 | 109143 |
| 12 | 489496 |
| 13 | 1430283 |
[1,4,7,28,67,289,723,3185,8677,38580,109143, 489496,1430283] |