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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 2 |
| 3 | 5 |
| 4 | 16 |
| 5 | 49 |
| 6 | 153 |
| 7 | 476 |
| 8 | 1483 |
| 9 | 4619 |
| 10 | 14388 |
| 11 | 44817 |
| 12 | 139601 |
| 13 | 434844 |
| 14 | 1354499 |
| 15 | 4219139 |
| 16 | 13142228 |
| 17 | 40936825 |
| 18 | 127514425 |
| 19 | 397195644 |
| 20 | 1237227707 |
| 21 | 3853849915 |
| 22 | 12004386164 |
| 23 | 37392552993 |
| 24 | 116474345313 |
| 25 | 362806816604 |
| 26 | 1130109689139 |
| 27 | 3520187193395 |
[0,2,5,16,49,153,476,1483,4619,14388,44817,139601, 434844,1354499,4219139,13142228,40936825, 127514425,397195644,1237227707,3853849915, 12004386164,37392552993,116474345313,362806816604, 1130109689139,3520187193395] |