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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 9 |
| 3 | 33 |
| 4 | 153 |
| 5 | 783 |
| 6 | 4329 |
| 7 | 26757 |
| 8 | 178929 |
| 9 | 1385019 |
| 10 | 13200489 |
| 11 | 136901097 |
| 12 | 1526386761 |
| 13 | 18967459527 |
| 14 | 242866024137 |
| 15 | 3134483671437 |
| 16 | 42179999959521 |
| 17 | 579952188438003 |
| 18 | 8370295687421001 |
| 19 | 133701888662298801 |
| 20 | 2247741025303683321 |
| 21 | 39543420776223234303 |
[1,3,9,33,153,783,4329,26757,178929,1385019, 13200489,136901097,1526386761,18967459527, 242866024137,3134483671437,42179999959521, 579952188438003,8370295687421001, 133701888662298801,2247741025303683321, 39543420776223234303] |