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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 15 |
| 3 | 165 |
| 4 | 2145 |
| 5 | 40755 |
| 6 | 1181895 |
| 7 | 43730115 |
| 8 | 2317696095 |
| 9 | 136744069605 |
| 10 | 8341388245905 |
| 11 | 558873012475635 |
| 12 | 46386460035477705 |
| 13 | 4685032463583248205 |
| 14 | 501298473603407557935 |
| 15 | 65670100042046390089485 |
| 16 | 9128143905844448222438415 |
| 17 | 1360093441970822785143323835 |
| 18 | 221695231041244113978361785105 |
[3,15,165,2145,40755,1181895,43730115,2317696095, 136744069605,8341388245905,558873012475635, 46386460035477705,4685032463583248205, 501298473603407557935,65670100042046390089485, 9128143905844448222438415, 1360093441970822785143323835, 221695231041244113978361785105] |