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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 15 |
| 2 | 127 |
| 3 | 1023 |
| 4 | 8191 |
| 5 | 65535 |
| 6 | 524287 |
| 7 | 4194303 |
| 8 | 33554431 |
| 9 | 268435455 |
| 10 | 2147483647 |
| 11 | 17179869183 |
| 12 | 137438953471 |
| 13 | 1099511627775 |
| 14 | 8796093022207 |
| 15 | 70368744177663 |
| 16 | 562949953421311 |
| 17 | 4503599627370495 |
| 18 | 36028797018963967 |
| 19 | 288230376151711743 |
| 20 | 2305843009213693951 |
| 21 | 18446744073709551615 |
[1,15,127,1023,8191,65535,524287,4194303,33554431, 268435455,2147483647,17179869183,137438953471, 1099511627775,8796093022207,70368744177663, 562949953421311,4503599627370495, 36028797018963967,288230376151711743, 2305843009213693951,18446744073709551615] |