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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 2 |
| 2 | 0 |
| 3 | 22 |
| 4 | 280 |
| 5 | 5402 |
| 6 | 515460 |
| 7 | 11703382 |
| 8 | 2688141040 |
| 9 | 146635350962 |
| 10 | 34251754225020 |
| 11 | 4629204580980142 |
| 12 | 993794187704175400 |
| 13 | 265705552906954222922 |
| 14 | 63184407507496166760180 |
[0,2,0,22,280,5402,515460,11703382,2688141040, 146635350962,34251754225020,4629204580980142, 993794187704175400,265705552906954222922, 63184407507496166760180] |