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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 23 |
| 5 | 55 |
| 6 | 311 |
| 7 | 823 |
| 8 | 1847 |
| 9 | 10039 |
| 10 | 26423 |
| 11 | 8415031 |
| 12 | 25192247 |
| 13 | 58746679 |
| 14 | 1132488503 |
| 15 | 3279972151 |
| 16 | 7574939447 |
| 17 | 16164874039 |
| 18 | 291042780983 |
| 19 | 840798594871 |
| 20 | 1940310222647 |
| 21 | 4139333478199 |
| 22 | 74508077655863 |
| 23 | 215245566011191 |
| 24 | 496720542721847 |
| 25 | 1059670496143159 |
[1,3,7,23,55,311,823,1847,10039,26423,8415031, 25192247,58746679,1132488503,3279972151, 7574939447,16164874039,291042780983,840798594871, 1940310222647,4139333478199,74508077655863, 215245566011191,496720542721847,1059670496143159] |