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| n | a(n) |
|---|---|
| 1 | 6 |
| 2 | 18 |
| 3 | 312 |
| 4 | 33352 |
| 5 | 20608352 |
| 6 | 69920063852 |
| 7 | 1279414854562952 |
| 8 | 126404181535040391152 |
| 9 | 67823930097039015417498752 |
| 10 | 198754894778868023542228903871252 |
[6,18,312,33352,20608352,69920063852, 1279414854562952,126404181535040391152, 67823930097039015417498752, 198754894778868023542228903871252] |