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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 6 |
| 5 | 24 |
| 6 | 120 |
| 7 | 720 |
| 8 | 5040 |
| 9 | 40320 |
| 10 | 0 |
| 11 | 39916800 |
| 12 | 239500800 |
| 13 | 2075673600 |
| 14 | 21794572800 |
| 15 | 261534873600 |
| 16 | 3487131648000 |
| 17 | 50812489728000 |
| 18 | 800296713216000 |
| 19 | 13516122267648000 |
| 20 | 0 |
| 21 | 25545471085854720000 |
| 22 | 281000181944401920000 |
| 23 | 4308669456480829440000 |
| 24 | 77556050216654929920000 |
[1,1,2,6,24,120,720,5040,40320,0,39916800, 239500800,2075673600,21794572800,261534873600, 3487131648000,50812489728000,800296713216000, 13516122267648000,0,25545471085854720000, 281000181944401920000,4308669456480829440000, 77556050216654929920000] |