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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 12 |
| 3 | 34 |
| 4 | 99 |
| 5 | 261 |
| 6 | 678 |
| 7 | 1692 |
| 8 | 4149 |
| 9 | 9959 |
| 10 | 23568 |
| 11 | 55014 |
| 12 | 127031 |
| 13 | 290457 |
| 14 | 658602 |
| 15 | 1482240 |
| 16 | 3314025 |
| 17 | 7365915 |
| 18 | 16285300 |
| 19 | 35832810 |
| 20 | 78500811 |
| 21 | 171293293 |
| 22 | 372412782 |
| 23 | 806963364 |
| 24 | 1743173469 |
| 25 | 3754782351 |
| 26 | 8066319768 |
| 27 | 17285917742 |
| 28 | 36957928479 |
| 29 | 78847115649 |
[1,3,12,34,99,261,678,1692,4149,9959,23568,55014, 127031,290457,658602,1482240,3314025,7365915, 16285300,35832810,78500811,171293293,372412782, 806963364,1743173469,3754782351,8066319768, 17285917742,36957928479,78847115649] |