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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 9 |
| 3 | 54 |
| 4 | 531 |
| 5 | 6498 |
| 6 | 101925 |
| 7 | 1920222 |
| 8 | 42251391 |
| 9 | 1067567850 |
| 10 | 30411486441 |
| 11 | 965077330374 |
| 12 | 33764590958571 |
| 13 | 1291198144146498 |
| 14 | 53587639922183757 |
| 15 | 2398901329112787630 |
| 16 | 115225387686206361495 |
| 17 | 5911249981088653607898 |
| 18 | 322592377196349009882513 |
[1,3,9,54,531,6498,101925,1920222,42251391, 1067567850,30411486441,965077330374, 33764590958571,1291198144146498,53587639922183757, 2398901329112787630,115225387686206361495, 5911249981088653607898,322592377196349009882513] |