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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 15 |
| 3 | 16 |
| 4 | 495 |
| 5 | 511 |
| 6 | 7649 |
| 7 | 8160 |
| 8 | 252449 |
| 9 | 260609 |
| 10 | 3900975 |
| 11 | 4161584 |
| 12 | 128748495 |
| 13 | 132910079 |
| 14 | 1989489601 |
| 15 | 2122399680 |
| 16 | 65661480001 |
| 17 | 67783879681 |
| 18 | 1014635795535 |
| 19 | 1082419675216 |
| 20 | 33487226052015 |
| 21 | 34569645727231 |
| 22 | 517462266233249 |
| 23 | 552031911960480 |
| 24 | 17078419625047649 |
[1,1,15,16,495,511,7649,8160,252449,260609, 3900975,4161584,128748495,132910079,1989489601, 2122399680,65661480001,67783879681,1014635795535, 1082419675216,33487226052015,34569645727231, 517462266233249,552031911960480,17078419625047649] |