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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 13 |
| 3 | 48 |
| 4 | 298 |
| 5 | 1520 |
| 6 | 8338 |
| 7 | 44976 |
| 8 | 244029 |
| 9 | 1322551 |
| 10 | 7171769 |
| 11 | 38885648 |
| 12 | 210854845 |
| 13 | 1143330649 |
| 14 | 6199601829 |
| 15 | 33616711696 |
| 16 | 182283373322 |
| 17 | 988413912488 |
| 18 | 5359579124490 |
| 19 | 29061800830768 |
| 20 | 157584813722329 |
| 21 | 854488462716575 |
[1,13,48,298,1520,8338,44976,244029,1322551, 7171769,38885648,210854845,1143330649,6199601829, 33616711696,182283373322,988413912488, 5359579124490,29061800830768,157584813722329, 854488462716575] |