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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 9 |
| 3 | 104 |
| 4 | 3100 |
| 5 | 240426 |
| 6 | 48701198 |
| 7 | 25827984000 |
| 8 | 35918144695449 |
| 9 | 131122853271308800 |
| 10 | 1257534350074853437169 |
| 11 | 31702044036778351719381288 |
| 12 | 2101697684255539834581694933161 |
| 13 | 366535920215589795393834358340163616 |
| 14 | 168206775805350065067062191670084869898100 |
| 15 | 203163556896501557829619000156420343686336512000 |
[1,2,9,104,3100,240426,48701198,25827984000, 35918144695449,131122853271308800, 1257534350074853437169,31702044036778351719381288, 2101697684255539834581694933161, 366535920215589795393834358340163616, 168206775805350065067062191670084869898100, 203163556896501557829619000156420343686336512000] |