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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 15 |
| 4 | 103 |
| 5 | 893 |
| 6 | 9341 |
| 7 | 114355 |
| 8 | 1603155 |
| 9 | 25318137 |
| 10 | 444689497 |
| 11 | 8597568671 |
| 12 | 181430298479 |
| 13 | 4149361409077 |
| 14 | 102229328244837 |
| 15 | 2699254206069387 |
| 16 | 76038064580742091 |
| 17 | 2276259442660623857 |
| 18 | 72160287650141753777 |
| 19 | 2414950992007231422007 |
[1,1,3,15,103,893,9341,114355,1603155,25318137, 444689497,8597568671,181430298479,4149361409077, 102229328244837,2699254206069387, 76038064580742091,2276259442660623857, 72160287650141753777,2414950992007231422007] |