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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 27 |
| 4 | 107 |
| 5 | 438 |
| 6 | 1845 |
| 7 | 7908 |
| 8 | 34303 |
| 9 | 150348 |
| 10 | 664775 |
| 11 | 2960079 |
| 12 | 13257289 |
| 13 | 59674848 |
| 14 | 269793959 |
| 15 | 1224411921 |
| 16 | 5575399047 |
| 17 | 25463488884 |
| 18 | 116605425929 |
| 19 | 535256505307 |
| 20 | 2462340230837 |
| 21 | 11349906044252 |
| 22 | 52410818984793 |
| 23 | 242420589719182 |
| 24 | 1123003680161339 |
| 25 | 5209618624112916 |
| 26 | 24199106376990991 |
| 27 | 112543832348913445 |
[1,2,7,27,107,438,1845,7908,34303,150348,664775, 2960079,13257289,59674848,269793959,1224411921, 5575399047,25463488884,116605425929,535256505307, 2462340230837,11349906044252,52410818984793, 242420589719182,1123003680161339,5209618624112916, 24199106376990991,112543832348913445] |