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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 320 |
| 3 | 9856080 |
| 4 | 111411200000000 |
| 5 | 758912215744345000000000 |
| 6 | 4641055652546245989752776320614400000 |
| 7 | 35539706227151665491451514343890494014992000000000000 |
| 8 | 453355203871266077337924186645041169745278527392553369600000000000000000 |
[1,2,320,9856080,111411200000000, 758912215744345000000000, 4641055652546245989752776320614400000, 35539706227151665491451514343890494014992000000000\ 000, 45335520387126607733792418664504116974527852739255\ 3369600000000000000000] |