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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 9 |
| 5 | 23 |
| 6 | 53 |
| 7 | 115 |
| 8 | 241 |
| 9 | 495 |
| 10 | 1005 |
| 11 | 2027 |
| 12 | 4073 |
| 13 | 8167 |
| 14 | 16357 |
| 15 | 32739 |
| 16 | 65505 |
| 17 | 131039 |
| 18 | 262109 |
| 19 | 524251 |
| 20 | 1048537 |
| 21 | 2097111 |
| 22 | 4194261 |
| 23 | 8388563 |
| 24 | 16777169 |
[0,1,3,9,23,53,115,241,495,1005,2027,4073,8167, 16357,32739,65505,131039,262109,524251,1048537, 2097111,4194261,8388563,16777169] |