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| n | a(n) |
|---|---|
| 1 | 540 |
| 2 | 3276 |
| 3 | 58032 |
| 4 | 950976 |
| 5 | 1862190 |
| 6 | 17660160 |
| 7 | 3925389312 |
| 8 | 1005014679552 |
| 9 | 16080326885376 |
| 10 | 17908023591648 |
| 11 | 43947421401888 |
| 12 | 92069057203200 |
| 13 | 207726054681600 |
| 14 | 411471933675264 |
| 15 | 12363050673792000 |
| 16 | 160893693946908502272 |
| 17 | 269783631952374398976 |
| 18 | 467406267507560908800 |
[540,3276,58032,950976,1862190,17660160, 3925389312,1005014679552,16080326885376, 17908023591648,43947421401888,92069057203200, 207726054681600,411471933675264,12363050673792000, 160893693946908502272,269783631952374398976, 467406267507560908800] |