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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 3 |
| 3 | 7 |
| 4 | 20 |
| 5 | 148 |
| 6 | 403 |
| 7 | 1096 |
| 8 | 1097 |
| 9 | 2980 |
| 10 | 2981 |
| 11 | 8103 |
| 12 | 59874 |
| 13 | 162755 |
| 14 | 442413 |
| 15 | 1202604 |
| 16 | 3269017 |
| 17 | 8886110 |
| 18 | 8886111 |
| 19 | 24154952 |
| 20 | 24154953 |
| 21 | 65659969 |
| 22 | 178482301 |
| 23 | 3584912846 |
| 24 | 9744803446 |
| 25 | 26489122130 |
| 26 | 72004899337 |
| 27 | 195729609428 |
[2,3,7,20,148,403,1096,1097,2980,2981,8103,59874, 162755,442413,1202604,3269017,8886110,8886111, 24154952,24154953,65659969,178482301,3584912846, 9744803446,26489122130,72004899337,195729609428] |