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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 8 |
| 4 | 56 |
| 5 | 672 |
| 6 | 13440 |
| 7 | 443520 |
| 8 | 23950080 |
| 9 | 2107607040 |
| 10 | 301387806720 |
| 11 | 69921971159040 |
| 12 | 26290661155799040 |
| 13 | 16011012643881615360 |
| 14 | 15786858466867272744960 |
| 15 | 25195826113120167300956160 |
| 16 | 65080818850189392138369761280 |
| 17 | 272037822793791659138385602150400 |
[1,1,2,8,56,672,13440,443520,23950080,2107607040, 301387806720,69921971159040,26290661155799040, 16011012643881615360,15786858466867272744960, 25195826113120167300956160, 65080818850189392138369761280, 272037822793791659138385602150400] |