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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 15 |
| 3 | 389 |
| 4 | 17687 |
| 5 | 1230957 |
| 6 | 121576879 |
| 7 | 16166877205 |
| 8 | 2784640846791 |
| 9 | 603078760252733 |
| 10 | 160399574539581023 |
| 11 | 51396542533525536741 |
| 12 | 19528343388372578867575 |
| 13 | 8681260357657270101974029 |
[1,15,389,17687,1230957,121576879,16166877205, 2784640846791,603078760252733,160399574539581023, 51396542533525536741,19528343388372578867575, 8681260357657270101974029] |