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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 6 |
| 4 | 28 |
| 5 | 45 |
| 6 | 120 |
| 7 | 496 |
| 8 | 672 |
| 9 | 6048 |
| 10 | 8128 |
| 11 | 14421 |
| 12 | 30240 |
| 13 | 32760 |
| 14 | 523776 |
| 15 | 2178540 |
| 16 | 23569920 |
| 17 | 26409026 |
| 18 | 29270772 |
| 19 | 30685402 |
| 20 | 33550336 |
| 21 | 45532800 |
[1,4,6,28,45,120,496,672,6048,8128,14421,30240, 32760,523776,2178540,23569920,26409026,29270772, 30685402,33550336,45532800] |