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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 7 |
| 2 | -7 |
| 3 | 23 |
| 4 | -121 |
| 5 | 481 |
| 6 | -3015581 |
| 7 | 67337 |
| 8 | -30135767 |
| 9 | 10946836702 |
| 10 | -369658793327 |
| 11 | 1633542173485 |
| 12 | -20836336617617359 |
| 13 | 28614002185051 |
| 14 | -10503257306519121539 |
| 15 | 55315660282703717655037 |
| 16 | -146269786633489194137851 |
| 17 | 256962811799649370068488 |
| 18 | -10500086267327643941391664345141 |
[1,7,-7,23,-121,481,-3015581,67337,-30135767, 10946836702,-369658793327,1633542173485, -20836336617617359,28614002185051, -10503257306519121539,55315660282703717655037, -146269786633489194137851, 256962811799649370068488, -10500086267327643941391664345141] |