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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 4 |
| 4 | 126 |
| 5 | 9367 |
| 6 | 1120780 |
| 7 | 189565588 |
| 8 | 43154533233 |
| 9 | 12735808866899 |
| 10 | 4732638168795171 |
| 11 | 2163220895025390670 |
| 12 | 1193176166690983987122 |
| 13 | 781607533669746761791541 |
[0,1,4,126,9367,1120780,189565588,43154533233, 12735808866899,4732638168795171, 2163220895025390670,1193176166690983987122, 781607533669746761791541] |