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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 9 |
| 3 | 61 |
| 4 | 546 |
| 5 | 6043 |
| 6 | 79475 |
| 7 | 1209160 |
| 8 | 20873685 |
| 9 | 402896615 |
| 10 | 8595041400 |
| 11 | 200773098515 |
| 12 | 5095839723205 |
| 13 | 139624739872970 |
| 14 | 4107177047046645 |
| 15 | 129087781738773385 |
| 16 | 4316962772836390050 |
| 17 | 153048896045632212175 |
| 18 | 5733602882337419294975 |
[1,2,9,61,546,6043,79475,1209160,20873685, 402896615,8595041400,200773098515,5095839723205, 139624739872970,4107177047046645, 129087781738773385,4316962772836390050, 153048896045632212175,5733602882337419294975] |