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| n | a(n) |
|---|---|
| 1 | 15 |
| 2 | 63 |
| 3 | 1023 |
| 4 | 16383 |
| 5 | 4194303 |
| 6 | 67108863 |
| 7 | 17179869183 |
| 8 | 274877906943 |
| 9 | 70368744177663 |
| 10 | 288230376151711743 |
| 11 | 4611686018427387903 |
| 12 | 18889465931478580854783 |
| 13 | 4835703278458516698824703 |
| 14 | 77371252455336267181195263 |
| 15 | 19807040628566084398385987583 |
[15,63,1023,16383,4194303,67108863,17179869183, 274877906943,70368744177663,288230376151711743, 4611686018427387903,18889465931478580854783, 4835703278458516698824703, 77371252455336267181195263, 19807040628566084398385987583] |