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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 12 |
| 4 | 38 |
| 5 | 114 |
| 6 | 386 |
| 7 | 1382 |
| 8 | 4822 |
| 9 | 17508 |
| 10 | 66394 |
| 11 | 250268 |
| 12 | 953578 |
| 13 | 3737668 |
| 14 | 14728014 |
| 15 | 58160096 |
| 16 | 233302828 |
| 17 | 944642728 |
| 18 | 3831196078 |
| 19 | 15657400600 |
| 20 | 64551140608 |
| 21 | 266981261146 |
| 22 | 1108425961502 |
| 23 | 4631228450076 |
| 24 | 19431298062940 |
| 25 | 81743875479558 |
| 26 | 345295001065368 |
| 27 | 1464496330522742 |
| 28 | 6227513695877568 |
[1,2,4,12,38,114,386,1382,4822,17508,66394,250268, 953578,3737668,14728014,58160096,233302828, 944642728,3831196078,15657400600,64551140608, 266981261146,1108425961502,4631228450076, 19431298062940,81743875479558,345295001065368, 1464496330522742,6227513695877568] |