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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 16 |
| 4 | 36 |
| 5 | 144 |
| 6 | 576 |
| 7 | 1296 |
| 8 | 3600 |
| 9 | 14400 |
| 10 | 32400 |
| 11 | 129600 |
| 12 | 705600 |
| 13 | 1587600 |
| 14 | 6350400 |
| 15 | 39690000 |
| 16 | 57153600 |
| 17 | 158760000 |
| 18 | 768398400 |
| 19 | 4802490000 |
| 20 | 6915585600 |
| 21 | 19209960000 |
| 22 | 129859329600 |
| 23 | 811620810000 |
| 24 | 1168733966400 |
| 25 | 3246483240000 |
| 26 | 29218349160000 |
| 27 | 159077678760000 |
[1,4,16,36,144,576,1296,3600,14400,32400,129600, 705600,1587600,6350400,39690000,57153600, 158760000,768398400,4802490000,6915585600, 19209960000,129859329600,811620810000, 1168733966400,3246483240000,29218349160000, 159077678760000] |