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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 13 |
| 3 | 73 |
| 4 | 527 |
| 5 | 4775 |
| 6 | 52589 |
| 7 | 683785 |
| 8 | 10257031 |
| 9 | 174370039 |
| 10 | 3313031765 |
| 11 | 69573669113 |
| 12 | 1600194393695 |
| 13 | 40004859850567 |
| 14 | 1080131215981693 |
| 15 | 31323805263501865 |
| 16 | 971037963168623351 |
| 17 | 32044252784564701655 |
| 18 | 1121548847459764820069 |
| 19 | 41497307356011298866841 |
| 20 | 1618394986884440656855375 |
[1,3,13,73,527,4775,52589,683785,10257031, 174370039,3313031765,69573669113,1600194393695, 40004859850567,1080131215981693,31323805263501865, 971037963168623351,32044252784564701655, 1121548847459764820069,41497307356011298866841, 1618394986884440656855375] |