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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 81 |
| 3 | 441 |
| 4 | 15129 |
| 5 | 281961 |
| 6 | 6487209 |
| 7 | 137945025 |
| 8 | 3020271849 |
| 9 | 65409597009 |
| 10 | 1422349620129 |
| 11 | 30882371810481 |
| 12 | 670905678011409 |
| 13 | 14572037106084249 |
| 14 | 316528933014939681 |
| 15 | 6875333045808325641 |
| 16 | 149340930039835655625 |
[0,81,441,15129,281961,6487209,137945025, 3020271849,65409597009,1422349620129, 30882371810481,670905678011409,14572037106084249, 316528933014939681,6875333045808325641, 149340930039835655625] |