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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 36 |
| 4 | 120 |
| 5 | 2520 |
| 6 | 277200 |
| 7 | 5045040 |
| 8 | 183783600 |
| 9 | 4655851200 |
| 10 | 80313433200 |
| 11 | 32607253879200 |
| 12 | 2743667504978400 |
| 13 | 58772246027695200 |
| 14 | 5038384364010597600 |
| 15 | 56517528952814529600 |
| 16 | 34089489546705963770400 |
| 17 | 7391221142626702144764000 |
[1,4,36,120,2520,277200,5045040,183783600, 4655851200,80313433200,32607253879200, 2743667504978400,58772246027695200, 5038384364010597600,56517528952814529600, 34089489546705963770400,7391221142626702144764000] |