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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | -6 |
| 3 | 36 |
| 4 | -266 |
| 5 | 2028 |
| 6 | -13596 |
| 7 | 50088 |
| 8 | 566694 |
| 9 | -16598580 |
| 10 | 232284876 |
| 11 | -1912070088 |
| 12 | 631155132 |
| 13 | 239439857272 |
| 14 | -2781218767224 |
| 15 | -17362458802992 |
| 16 | 795693633448710 |
| 17 | -458070639409908 |
| 18 | -335724554310292548 |
| 19 | 4520379769156382616 |
| 20 | 109439050270732883028 |
| 21 | -3828757746830590219608 |
[1,2,-6,36,-266,2028,-13596,50088,566694, -16598580,232284876,-1912070088,631155132, 239439857272,-2781218767224,-17362458802992, 795693633448710,-458070639409908, -335724554310292548,4520379769156382616, 109439050270732883028,-3828757746830590219608] |