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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 26 |
| 3 | 57 |
| 4 | 247 |
| 5 | 502 |
| 6 | 4083 |
| 7 | 1073741793 |
| 8 | 4294967263 |
| 9 | 8589934558 |
| 10 | 70368744177617 |
| 11 | 4503599627370443 |
| 12 | 4611686018427387841 |
| 13 | 18889465931478580854709 |
| 14 | 75557863725914323419059 |
| 15 | 77371252455336267181195177 |
| 16 | 316912650057057350374175801245 |
[4,26,57,247,502,4083,1073741793,4294967263, 8589934558,70368744177617,4503599627370443, 4611686018427387841,18889465931478580854709, 75557863725914323419059, 77371252455336267181195177, 316912650057057350374175801245] |