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| n | a(n) |
|---|---|
| 1 | 7 |
| 2 | 49 |
| 3 | 337 |
| 4 | 2311 |
| 5 | 15816 |
| 6 | 108032 |
| 7 | 736525 |
| 8 | 5012171 |
| 9 | 34047931 |
| 10 | 230889543 |
| 11 | 1563104184 |
| 12 | 10564826628 |
| 13 | 71293105297 |
| 14 | 480355314513 |
| 15 | 3231663192859 |
| 16 | 21709801573961 |
| 17 | 145636117720769 |
| 18 | 975623832619371 |
| 19 | 6526972402359763 |
| 20 | 43608650962250889 |
[7,49,337,2311,15816,108032,736525,5012171, 34047931,230889543,1563104184,10564826628, 71293105297,480355314513,3231663192859, 21709801573961,145636117720769,975623832619371, 6526972402359763,43608650962250889] |