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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 7 |
| 2 | 35 |
| 3 | 105 |
| 4 | 273 |
| 5 | 4095 |
| 6 | 38115 |
| 7 | 86625 |
| 8 | 540225 |
| 9 | 22444695 |
| 10 | 215417475 |
| 11 | 1819488825 |
| 12 | 18942548625 |
| 13 | 273922023375 |
| 14 | 9015078147075 |
| 15 | 69890980784625 |
| 16 | -152873391045375 |
| 17 | 34948775541054375 |
| 18 | 718624343013451875 |
| 19 | 6694758964203935625 |
[1,7,35,105,273,4095,38115,86625,540225,22444695, 215417475,1819488825,18942548625,273922023375, 9015078147075,69890980784625,-152873391045375, 34948775541054375,718624343013451875, 6694758964203935625] |