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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 40 |
| 2 | 1598 |
| 3 | 63760 |
| 4 | 2540812 |
| 5 | 101122400 |
| 6 | 4019487880 |
| 7 | 159566046400 |
| 8 | 6326369025680 |
| 9 | 250501704284800 |
| 10 | 9906193528929760 |
| 11 | 391237707071494400 |
| 12 | 15431572025223321280 |
| 13 | 607873176039216985600 |
| 14 | 23913706168912873070720 |
[1,40,1598,63760,2540812,101122400,4019487880, 159566046400,6326369025680,250501704284800, 9906193528929760,391237707071494400, 15431572025223321280,607873176039216985600, 23913706168912873070720] |