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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 35 |
| 3 | 207 |
| 4 | 1251 |
| 5 | 7678 |
| 6 | 47658 |
| 7 | 298371 |
| 8 | 1880659 |
| 9 | 11918586 |
| 10 | 75871710 |
| 11 | 484793950 |
| 12 | 3107494430 |
| 13 | 19973075580 |
| 14 | 128678167220 |
| 15 | 830735862179 |
| 16 | 5372968238979 |
| 17 | 34807369089378 |
| 18 | 225818672567382 |
| 19 | 1466956891774602 |
| 20 | 9540909022501226 |
| 21 | 62119854068610436 |
| 22 | 404854330511525580 |
[1,6,35,207,1251,7678,47658,298371,1880659, 11918586,75871710,484793950,3107494430, 19973075580,128678167220,830735862179, 5372968238979,34807369089378,225818672567382, 1466956891774602,9540909022501226, 62119854068610436,404854330511525580] |