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| n | a(n) |
|---|---|
| 0 | 15 |
| 1 | 61 |
| 2 | 198 |
| 3 | 1447 |
| 4 | 4539 |
| 5 | 19603 |
| 6 | 592629 |
| 7 | 2390119 |
| 8 | 7762986 |
| 9 | 56731021 |
| 10 | 177956049 |
| 11 | 768555217 |
| 12 | 23234612559 |
| 13 | 93707005453 |
| 14 | 304355628918 |
| 15 | 2224196407879 |
| 16 | 6976944852555 |
| 17 | 30131975818099 |
| 18 | 910936219395525 |
| 19 | 3673876853400199 |
| 20 | 11932566779596122 |
| 21 | 87201844310573053 |
[15,61,198,1447,4539,19603,592629,2390119,7762986, 56731021,177956049,768555217,23234612559, 93707005453,304355628918,2224196407879, 6976944852555,30131975818099,910936219395525, 3673876853400199,11932566779596122, 87201844310573053] |