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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | -1 |
| 3 | 5 |
| 4 | -15 |
| 5 | -489 |
| 6 | -2865 |
| 7 | 35685 |
| 8 | -135135 |
| 9 | -5897745 |
| 10 | 58437855 |
| 11 | 3061162125 |
| 12 | -39296062575 |
| 13 | -2278224696825 |
| 14 | -33411730777425 |
| 15 | -1496722493140875 |
| 16 | -6190283353629375 |
| 17 | -1563094742062478625 |
| 18 | -17805713551427426625 |
| 19 | 1456700757237661060125 |
| 20 | 11729538718345143320625 |
[1,-1,5,-15,-489,-2865,35685,-135135,-5897745, 58437855,3061162125,-39296062575,-2278224696825, -33411730777425,-1496722493140875, -6190283353629375,-1563094742062478625, -17805713551427426625,1456700757237661060125, 11729538718345143320625] |