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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 15 |
| 3 | 105 |
| 4 | 2016 |
| 5 | 11628 |
| 6 | 203203 |
| 7 | 1152921 |
| 8 | 19968040 |
| 9 | 113108320 |
| 10 | 1957220895 |
| 11 | 11084786065 |
| 12 | 191793185496 |
| 13 | 1086209028828 |
| 14 | 18793829460003 |
| 15 | 106437529743441 |
| 16 | 1841604033412080 |
| 17 | 10429792989769440 |
| 18 | 180458406785594575 |
| 19 | 1022013288177368025 |
| 20 | 17683082313822046576 |
[0,15,105,2016,11628,203203,1152921,19968040, 113108320,1957220895,11084786065,191793185496, 1086209028828,18793829460003,106437529743441, 1841604033412080,10429792989769440, 180458406785594575,1022013288177368025, 17683082313822046576] |