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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -2 |
| 2 | 6 |
| 3 | -14 |
| 4 | 36 |
| 5 | -88 |
| 6 | 220 |
| 7 | -544 |
| 8 | 1352 |
| 9 | -3352 |
| 10 | 8320 |
| 11 | -20640 |
| 12 | 51216 |
| 13 | -127072 |
| 14 | 315296 |
| 15 | -782304 |
| 16 | 1941056 |
| 17 | -4816128 |
| 18 | 11949760 |
| 19 | -29649664 |
| 20 | 73566592 |
| 21 | -182532992 |
| 22 | 452899840 |
| 23 | -1123732480 |
| 24 | 2788198656 |
| 25 | -6918062592 |
| 26 | 17165057536 |
| 27 | -42589842944 |
| 28 | 105673675776 |
| 29 | -262196922368 |
[1,-2,6,-14,36,-88,220,-544,1352,-3352,8320, -20640,51216,-127072,315296,-782304,1941056, -4816128,11949760,-29649664,73566592,-182532992, 452899840,-1123732480,2788198656,-6918062592, 17165057536,-42589842944,105673675776, -262196922368] |