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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 3 |
| 5 | 12 |
| 6 | 88 |
| 7 | 732 |
| 8 | 10258 |
| 9 | 249976 |
| 10 | 11455832 |
| 11 | 994987528 |
| 12 | 163053176864 |
| 13 | 50171849022768 |
| 14 | 28953151594499584 |
| 15 | 31368377658489837792 |
| 16 | 63938162732587949277392 |
| 17 | 245807862122123877567929920 |
| 18 | 1787085853417304634682510751296 |
| 19 | 24634234097674713300981911735051072 |
[1,0,0,0,3,12,88,732,10258,249976,11455832, 994987528,163053176864,50171849022768, 28953151594499584,31368377658489837792, 63938162732587949277392, 245807862122123877567929920, 1787085853417304634682510751296, 24634234097674713300981911735051072] |