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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 17 |
| 4 | 127 |
| 5 | 1249 |
| 6 | 15551 |
| 7 | 235297 |
| 8 | 4194303 |
| 9 | 86093441 |
| 10 | 1999999999 |
| 11 | 51874849201 |
| 12 | 1486016741375 |
| 13 | 46596170244961 |
| 14 | 1587429546508287 |
| 15 | 58385852050781249 |
| 16 | 2305843009213693951 |
| 17 | 97322383751333736961 |
| 18 | 4371823119477393063935 |
[1,3,17,127,1249,15551,235297,4194303,86093441, 1999999999,51874849201,1486016741375, 46596170244961,1587429546508287,58385852050781249, 2305843009213693951,97322383751333736961, 4371823119477393063935] |