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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 18 |
| 2 | 426 |
| 3 | 15402 |
| 4 | 822954 |
| 5 | 61796298 |
| 6 | 6241779786 |
| 7 | 818474614122 |
| 8 | 135406656802794 |
| 9 | 27612620496455178 |
| 10 | 6808731437920094346 |
| 11 | 1997715795041570812842 |
| 12 | 688004411488219400750634 |
| 13 | 274892797454182595423594058 |
| 14 | 126140171858432431734157512906 |
| 15 | 65889765750203313093270839555562 |
[1,18,426,15402,822954,61796298,6241779786, 818474614122,135406656802794,27612620496455178, 6808731437920094346,1997715795041570812842, 688004411488219400750634, 274892797454182595423594058, 126140171858432431734157512906, 65889765750203313093270839555562] |