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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 24 |
| 3 | 287 |
| 4 | 4082 |
| 5 | 63854 |
| 6 | 1060893 |
| 7 | 18375481 |
| 8 | 328140158 |
| 9 | 5998110712 |
| 10 | 111679078694 |
| 11 | 2110614752092 |
| 12 | 40383196151858 |
| 13 | 780713537950989 |
| 14 | 15227082192168750 |
| 15 | 299259411611190032 |
| 16 | 5920512681769082585 |
| 17 | 117815581575201608792 |
| 18 | 2356618411595244754811 |
| 19 | 47356204772093822680868 |
| 20 | 955566142938585617722546 |
[1,3,24,287,4082,63854,1060893,18375481,328140158, 5998110712,111679078694,2110614752092, 40383196151858,780713537950989,15227082192168750, 299259411611190032,5920512681769082585, 117815581575201608792,2356618411595244754811, 47356204772093822680868,955566142938585617722546] |