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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 15 |
| 3 | 63 |
| 4 | 253 |
| 5 | 1009 |
| 6 | 4033 |
| 7 | 16129 |
| 8 | 64511 |
| 9 | 258015 |
| 10 | 1031935 |
| 11 | 4127233 |
| 12 | 16506913 |
| 13 | 66019585 |
| 14 | 264046081 |
| 15 | 1056055299 |
| 16 | 4223705151 |
| 17 | 16892756671 |
| 18 | 67562771965 |
| 19 | 270218073025 |
| 20 | 1080740248897 |
| 21 | 4322432887297 |
| 22 | 17287619374079 |
| 23 | 69142029827999 |
[3,15,63,253,1009,4033,16129,64511,258015,1031935, 4127233,16506913,66019585,264046081,1056055299, 4223705151,16892756671,67562771965,270218073025, 1080740248897,4322432887297,17287619374079, 69142029827999] |