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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 0 |
| 8 | 0 |
| 9 | 0 |
| 10 | 226800 |
| 11 | 2494800 |
| 12 | 29937600 |
| 13 | 259459200 |
| 14 | 1816214400 |
| 15 | 10897286400 |
| 16 | 301491590400 |
| 17 | 4419628012800 |
| 18 | 51209462304000 |
| 19 | 482551041772800 |
| 20 | 6979977625420800 |
| 21 | 92611036249804800 |
| 22 | 2078225819199129600 |
[0,0,0,0,0,0,0,0,0,226800,2494800,29937600, 259459200,1816214400,10897286400,301491590400, 4419628012800,51209462304000,482551041772800, 6979977625420800,92611036249804800, 2078225819199129600] |