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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 120 |
| 6 | 360 |
| 7 | 2520 |
| 8 | 20160 |
| 9 | 60480 |
| 10 | 604800 |
| 11 | 6652800 |
| 12 | 19958400 |
| 13 | 259459200 |
| 14 | 3632428800 |
| 15 | 10897286400 |
| 16 | 174356582400 |
| 17 | 2964061900800 |
| 18 | 8892185702400 |
| 19 | 168951528345600 |
| 20 | 3379030566912000 |
| 21 | 10137091700736000 |
| 22 | 223016017416192000 |
| 23 | 5129368400572416000 |
[1,1,2,6,24,120,360,2520,20160,60480,604800, 6652800,19958400,259459200,3632428800,10897286400, 174356582400,2964061900800,8892185702400, 168951528345600,3379030566912000, 10137091700736000,223016017416192000, 5129368400572416000] |