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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -15 |
| 2 | -75 |
| 3 | -875 |
| 4 | -13125 |
| 5 | -223125 |
| 6 | -4090625 |
| 7 | -78890625 |
| 8 | -1577812500 |
| 9 | -32432812500 |
| 10 | -681089062500 |
| 11 | -14550539062500 |
| 12 | -315261679687500 |
| 13 | -6911506054687500 |
| 14 | -153040491210937500 |
| 15 | -3417904303710937500 |
[1,-15,-75,-875,-13125,-223125,-4090625,-78890625, -1577812500,-32432812500,-681089062500, -14550539062500,-315261679687500, -6911506054687500,-153040491210937500, -3417904303710937500] |