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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 4 |
| 3 | 17 |
| 4 | 17 |
| 5 | 64 |
| 6 | 64 |
| 7 | 375 |
| 8 | 375 |
| 9 | 2319 |
| 10 | 2319 |
| 11 | 15130 |
| 12 | 15130 |
| 13 | 99554 |
| 14 | 99554 |
| 15 | 675166 |
| 16 | 675166 |
| 17 | 4753617 |
| 18 | 4753617 |
| 19 | 33752394 |
| 20 | 33752394 |
| 21 | 239605153 |
| 22 | 239605153 |
[4,4,17,17,64,64,375,375,2319,2319,15130,15130, 99554,99554,675166,675166,4753617,4753617, 33752394,33752394,239605153,239605153] |