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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 9 |
| 3 | 9 |
| 4 | 49 |
| 5 | 225 |
| 6 | 961 |
| 7 | 3969 |
| 8 | 16129 |
| 9 | 65025 |
| 10 | 261121 |
| 11 | 1046529 |
| 12 | 4190209 |
| 13 | 16769025 |
| 14 | 67092481 |
| 15 | 268402689 |
| 16 | 1073676289 |
| 17 | 4294836225 |
| 18 | 17179607041 |
| 19 | 68718952449 |
| 20 | 274876858369 |
| 21 | 1099509530625 |
| 22 | 4398042316801 |
| 23 | 17592177655809 |
[4,9,9,49,225,961,3969,16129,65025,261121,1046529, 4190209,16769025,67092481,268402689,1073676289, 4294836225,17179607041,68718952449,274876858369, 1099509530625,4398042316801,17592177655809] |