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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 13 |
| 2 | 8191 |
| 3 | 797161 |
| 4 | 22369621 |
| 5 | 305175781 |
| 6 | 2612138803 |
| 7 | 16148168401 |
| 8 | 78536544841 |
| 9 | 317733228541 |
| 10 | 1111111111111 |
| 11 | 3452271214393 |
| 12 | 9726655034461 |
| 13 | 25239592216021 |
| 14 | 61054982558011 |
| 15 | 139013933454241 |
| 16 | 300239975158033 |
| 17 | 619036127056621 |
| 18 | 1224880286215951 |
| 19 | 2336276859014281 |
| 20 | 4311578947368421 |
[1,13,8191,797161,22369621,305175781,2612138803, 16148168401,78536544841,317733228541, 1111111111111,3452271214393,9726655034461, 25239592216021,61054982558011,139013933454241, 300239975158033,619036127056621,1224880286215951, 2336276859014281,4311578947368421] |