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| n | a(n) |
|---|---|
| 1 | 21 |
| 2 | 81 |
| 3 | 1188 |
| 4 | 14793 |
| 5 | 156964 |
| 6 | 1767430 |
| 7 | 21435360 |
| 8 | 259297241 |
| 9 | 2992271478 |
| 10 | 32522357305 |
| 11 | 335372829196 |
| 12 | 3312669542090 |
| 13 | 31487964667940 |
| 14 | 288434629481468 |
| 15 | 2549339374347045 |
| 16 | 21786411636714179 |
| 17 | 180452978644995861 |
[21,81,1188,14793,156964,1767430,21435360, 259297241,2992271478,32522357305,335372829196, 3312669542090,31487964667940,288434629481468, 2549339374347045,21786411636714179, 180452978644995861] |