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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 15 |
| 3 | 75 |
| 4 | 391 |
| 5 | 2065 |
| 6 | 11091 |
| 7 | 60215 |
| 8 | 330003 |
| 9 | 1820869 |
| 10 | 10103153 |
| 11 | 56313047 |
| 12 | 315071801 |
| 13 | 1768489771 |
| 14 | 9953853677 |
| 15 | 56158682949 |
| 16 | 317505199769 |
| 17 | 1798402412539 |
[1,3,15,75,391,2065,11091,60215,330003,1820869, 10103153,56313047,315071801,1768489771,9953853677, 56158682949,317505199769,1798402412539] |