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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 72 |
| 4 | 1800 |
| 5 | 529200 |
| 6 | 64033200 |
| 7 | 21643221600 |
| 8 | 6254891042400 |
| 9 | 2258015666306400 |
| 10 | 17917354312141284000 |
| 11 | 15068494976510819844000 |
| 12 | 28961647344853795740168000 |
| 13 | 39648495215104846368289992000 |
| 14 | 66649120456591246745095476552000 |
| 15 | 123234223724237215231681536144648000 |
| 16 | 1905570801447880059127491593404692024000 |
[1,4,72,1800,529200,64033200,21643221600, 6254891042400,2258015666306400, 17917354312141284000,15068494976510819844000, 28961647344853795740168000, 39648495215104846368289992000, 66649120456591246745095476552000, 123234223724237215231681536144648000, 1905570801447880059127491593404692024000] |