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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 120 |
| 6 | 720 |
| 7 | 3600 |
| 8 | 15600 |
| 9 | 61872 |
| 10 | 236388 |
| 11 | 901748 |
| 12 | 3509106 |
| 13 | 13716168 |
| 14 | 53327912 |
| 15 | 205176192 |
| 16 | 780194112 |
| 17 | 2937412512 |
| 18 | 10991746368 |
| 19 | 40961976672 |
| 20 | 152144989056 |
| 21 | 563313879080 |
| 22 | 2078732476328 |
| 23 | 7644789439842 |
| 24 | 28024241472936 |
| 25 | 102432262746504 |
[1,2,6,24,120,720,3600,15600,61872,236388,901748, 3509106,13716168,53327912,205176192,780194112, 2937412512,10991746368,40961976672,152144989056, 563313879080,2078732476328,7644789439842, 28024241472936,102432262746504] |