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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 17 |
| 6 | 31 |
| 7 | 1 |
| 8 | 5461 |
| 9 | 257 |
| 10 | 73 |
| 11 | 1271 |
| 12 | 60787 |
| 13 | 241 |
| 14 | 22369621 |
| 15 | 617093 |
| 16 | 49981 |
| 17 | 16843009 |
| 18 | 5726623061 |
| 19 | 7957 |
| 20 | 91625968981 |
| 21 | 61681 |
| 22 | 231927781 |
| 23 | 50991843607 |
| 24 | 499069107643 |
| 25 | 4043309297 |
| 26 | 1100586419201 |
| 27 | 5664905191661 |
| 28 | 1672180312771 |
[1,1,1,17,31,1,5461,257,73,1271,60787,241, 22369621,617093,49981,16843009,5726623061,7957, 91625968981,61681,231927781,50991843607, 499069107643,4043309297,1100586419201, 5664905191661,1672180312771] |