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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 28 |
| 3 | 872 |
| 4 | 47248 |
| 5 | 3907232 |
| 6 | 454886848 |
| 7 | 70597546112 |
| 8 | 14042505449728 |
| 9 | 3475021574246912 |
| 10 | 1045247734061145088 |
| 11 | 375054668796817221632 |
| 12 | 158085597663328138006528 |
| 13 | 77269840864693331267919872 |
[1,2,28,872,47248,3907232,454886848,70597546112, 14042505449728,3475021574246912, 1045247734061145088,375054668796817221632, 158085597663328138006528, 77269840864693331267919872] |