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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 5 |
| 2 | 70 |
| 3 | 1696 |
| 4 | 49493 |
| 5 | 1593861 |
| 6 | 54591225 |
| 7 | 1950653202 |
| 8 | 71889214644 |
| 9 | 2712628146949 |
| 10 | 104277713515456 |
| 11 | 4069334248174800 |
| 12 | 160785480249706192 |
| 13 | 6419443865094494044 |
| 14 | 258585021917711797850 |
| 15 | 10496205397574996367474 |
| 16 | 428899108081734423242550 |
| 17 | 17628723180468295514015268 |
| 18 | 728347675604866545590505024 |
[1,5,70,1696,49493,1593861,54591225,1950653202, 71889214644,2712628146949,104277713515456, 4069334248174800,160785480249706192, 6419443865094494044,258585021917711797850, 10496205397574996367474,428899108081734423242550, 17628723180468295514015268, 728347675604866545590505024] |