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| n | a(n) |
|---|---|
| 0 | 4 |
| 1 | 16 |
| 2 | 96 |
| 3 | 768 |
| 4 | 7680 |
| 5 | 92160 |
| 6 | 1290240 |
| 7 | 20643840 |
| 8 | 371589120 |
| 9 | 7431782400 |
| 10 | 163499212800 |
| 11 | 3923981107200 |
| 12 | 102023508787200 |
| 13 | 2856658246041600 |
| 14 | 85699747381248000 |
| 15 | 2742391916199936000 |
| 16 | 93241325150797824000 |
| 17 | 3356687705428721664000 |
| 18 | 127554132806291423232000 |
[4,16,96,768,7680,92160,1290240,20643840, 371589120,7431782400,163499212800,3923981107200, 102023508787200,2856658246041600, 85699747381248000,2742391916199936000, 93241325150797824000,3356687705428721664000, 127554132806291423232000] |