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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 15 |
| 2 | 121 |
| 3 | 3867 |
| 4 | 30943 |
| 5 | 495067 |
| 6 | 3960569 |
| 7 | 253475987 |
| 8 | 2027808611 |
| 9 | 32444935345 |
| 10 | 259559486959 |
| 11 | 8305903553295 |
| 12 | 66447228478363 |
| 13 | 1063155655468083 |
| 14 | 8505245244078969 |
| 15 | 1088671391232413187 |
[1,15,121,3867,30943,495067,3960569,253475987, 2027808611,32444935345,259559486959,8305903553295, 66447228478363,1063155655468083,8505245244078969, 1088671391232413187] |