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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 21 |
| 3 | 255 |
| 4 | 4725 |
| 5 | 123903 |
| 6 | 4368729 |
| 7 | 199467243 |
| 8 | 11455187445 |
| 9 | 808475761695 |
| 10 | 68805857523321 |
| 11 | 6950458374996843 |
| 12 | 822292004658568761 |
| 13 | 112639503374757412875 |
| 14 | 17688916392275574761805 |
| 15 | 3157133540377493872350855 |
| 16 | 635546443798928578953138165 |
[1,3,21,255,4725,123903,4368729,199467243, 11455187445,808475761695,68805857523321, 6950458374996843,822292004658568761, 112639503374757412875,17688916392275574761805, 3157133540377493872350855, 635546443798928578953138165] |