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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 24 |
| 2 | 432 |
| 3 | 4440 |
| 4 | 21024 |
| 5 | 87696 |
| 6 | 559440 |
| 7 | 1395264 |
| 8 | 5728320 |
| 9 | 23852760 |
| 10 | 64719648 |
| 11 | 183528288 |
| 12 | 898460640 |
| 13 | 1765134672 |
| 14 | 6002425728 |
| 15 | 21820957200 |
| 16 | 52895150208 |
| 17 | 134056553904 |
| 18 | 598084104240 |
| 19 | 1090757945760 |
| 20 | 3530801969856 |
| 21 | 11795485116480 |
| 22 | 26821191064896 |
| 23 | 65724336729792 |
[1,24,432,4440,21024,87696,559440,1395264,5728320, 23852760,64719648,183528288,898460640,1765134672, 6002425728,21820957200,52895150208,134056553904, 598084104240,1090757945760,3530801969856, 11795485116480,26821191064896,65724336729792] |