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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 28 |
| 3 | 410 |
| 4 | 7204 |
| 5 | 121826 |
| 6 | 2072344 |
| 7 | 35217368 |
| 8 | 598579468 |
| 9 | 10173619772 |
| 10 | 172914342028 |
| 11 | 2938909630526 |
| 12 | 49950690508336 |
| 13 | 848978618084774 |
| 14 | 14429524172090140 |
| 15 | 245249012515926980 |
| 16 | 4168334134059809248 |
[0,28,410,7204,121826,2072344,35217368,598579468, 10173619772,172914342028,2938909630526, 49950690508336,848978618084774,14429524172090140, 245249012515926980,4168334134059809248] |