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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 14 |
| 3 | 440 |
| 4 | 14115134 |
| 5 | 466518785395590988060 |
| 6 | 16843102905928252175005299732280541221280287736370800875201510 |
[4,14,440,14115134,466518785395590988060, 16843102905928252175005299732280541221280287736370\ 800875201510] |