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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 6 |
| 3 | 4 |
| 4 | 50 |
| 5 | 397 |
| 6 | 496 |
| 7 | 4167 |
| 8 | 15052 |
| 9 | 30627 |
| 10 | 182105 |
| 11 | 550497 |
| 12 | 447673 |
| 13 | 3143598 |
| 14 | 4821309 |
| 15 | 19552188 |
| 16 | 67889102 |
| 17 | 109303021 |
| 18 | 378355224 |
[1,6,4,50,397,496,4167,15052,30627,182105,550497, 447673,3143598,4821309,19552188,67889102, 109303021,378355224] |