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| n | a(n) |
|---|---|
| 1 | 15 |
| 2 | 525 |
| 3 | 6723 |
| 4 | 58409 |
| 5 | 426289 |
| 6 | 2918103 |
| 7 | 19899645 |
| 8 | 139354433 |
| 9 | 1014707218 |
| 10 | 7708112426 |
| 11 | 61057289906 |
| 12 | 503473697674 |
| 13 | 4313566395798 |
| 14 | 38328567460364 |
| 15 | 352618771825166 |
| 16 | 3353663922642364 |
| 17 | 32927374508631249 |
| 18 | 333319732229912935 |
[15,525,6723,58409,426289,2918103,19899645, 139354433,1014707218,7708112426,61057289906, 503473697674,4313566395798,38328567460364, 352618771825166,3353663922642364, 32927374508631249,333319732229912935] |