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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 18 |
| 3 | -18 |
| 4 | -270 |
| 5 | 486 |
| 6 | 7938 |
| 7 | -17010 |
| 8 | -290142 |
| 9 | 676998 |
| 10 | 11852082 |
| 11 | -29091474 |
| 12 | -518183406 |
| 13 | 1315388646 |
| 14 | 23720180130 |
| 15 | -61672468338 |
| 16 | -1122411776958 |
| 17 | 2971089997830 |
| 18 | 54459919690578 |
| 19 | -146181889695762 |
| 20 | -2694816626063310 |
| 21 | 7314502270743270 |
| 22 | 135469313469987138 |
[1,6,18,-18,-270,486,7938,-17010,-290142,676998, 11852082,-29091474,-518183406,1315388646, 23720180130,-61672468338,-1122411776958, 2971089997830,54459919690578,-146181889695762, -2694816626063310,7314502270743270, 135469313469987138] |