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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 7 |
| 5 | 24 |
| 6 | 172 |
| 7 | 173 |
| 8 | 218 |
| 9 | 439 |
| 10 | 2563 |
| 11 | 2782 |
| 12 | 2880 |
| 13 | 3715 |
| 14 | 4392 |
| 15 | 10820 |
| 16 | 14592 |
| 17 | 25054 |
| 18 | 27769 |
| 19 | 40168 |
| 20 | 180992 |
| 21 | 193907 |
[1,2,4,7,24,172,173,218,439,2563,2782,2880,3715, 4392,10820,14592,25054,27769,40168,180992,193907] |