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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | -1 |
| 4 | -7 |
| 5 | 9 |
| 6 | 169 |
| 7 | -225 |
| 8 | -8751 |
| 9 | 11025 |
| 10 | 789681 |
| 11 | -893025 |
| 12 | -110381943 |
| 13 | 108056025 |
| 14 | 22142611737 |
| 15 | -18261468225 |
| 16 | -6041067843807 |
| 17 | 4108830350625 |
| 18 | 2153812782224097 |
| 19 | -1187451971330625 |
| 20 | -972958293249140583 |
[1,1,1,-1,-7,9,169,-225,-8751,11025,789681, -893025,-110381943,108056025,22142611737, -18261468225,-6041067843807,4108830350625, 2153812782224097,-1187451971330625, -972958293249140583] |