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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 15 |
| 4 | 91 |
| 5 | 601 |
| 6 | 4155 |
| 7 | 29553 |
| 8 | 214303 |
| 9 | 1575931 |
| 10 | 11712599 |
| 11 | 87776507 |
| 12 | 662224819 |
| 13 | 5023611579 |
| 14 | 38284084575 |
| 15 | 292892970967 |
| 16 | 2248271735299 |
| 17 | 17307950940833 |
| 18 | 133580448494227 |
| 19 | 1033263820897777 |
| 20 | 8008342899292167 |
| 21 | 62179343789159945 |
| 22 | 483553052098053915 |
[1,1,3,15,91,601,4155,29553,214303,1575931, 11712599,87776507,662224819,5023611579, 38284084575,292892970967,2248271735299, 17307950940833,133580448494227,1033263820897777, 8008342899292167,62179343789159945, 483553052098053915] |