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| n | a(n) |
|---|---|
| 1 | 15 |
| 2 | 1687 |
| 3 | 69792 |
| 4 | 2736666 |
| 5 | 123176874 |
| 6 | 5641347668 |
| 7 | 249947653938 |
| 8 | 11092958334732 |
| 9 | 494534011115264 |
| 10 | 22060105603804064 |
| 11 | 982920625501269624 |
| 12 | 43799276302849495414 |
| 13 | 1952019382459362360458 |
| 14 | 86999072734508636631708 |
[15,1687,69792,2736666,123176874,5641347668, 249947653938,11092958334732,494534011115264, 22060105603804064,982920625501269624, 43799276302849495414,1952019382459362360458, 86999072734508636631708] |