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| n | a(n) |
|---|---|
| 1 | 247 |
| 2 | 988 |
| 3 | 2808 |
| 4 | 10440 |
| 5 | 87696 |
| 6 | 151200 |
| 7 | 191052 |
| 8 | 263520 |
| 9 | 2630320 |
| 10 | 3961980 |
[247,988,2808,10440,87696,151200,191052,263520, 2630320,3961980] |