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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 15 |
| 3 | 280 |
| 4 | 5295 |
| 5 | 101460 |
| 6 | 1999365 |
| 7 | 40210161 |
| 8 | 820951127 |
| 9 | 16962540224 |
| 10 | 353916457700 |
| 11 | 7444303111792 |
| 12 | 157654572063308 |
| 13 | 3358267477535756 |
| 14 | 71896125048485001 |
| 15 | 1545960357028561441 |
| 16 | 33370692254737883179 |
[1,15,280,5295,101460,1999365,40210161,820951127, 16962540224,353916457700,7444303111792, 157654572063308,3358267477535756, 71896125048485001,1545960357028561441, 33370692254737883179] |