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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 25 |
| 3 | 147 |
| 4 | 1089 |
| 5 | 20449 |
| 6 | 48841 |
| 7 | 312987 |
| 8 | 55190041 |
| 9 | 14322675 |
| 10 | 100100025 |
| 11 | 32065374675 |
| 12 | 4546130625 |
| 13 | 29873533563 |
| 14 | 1859904071089 |
| 15 | 4089135109921 |
| 16 | 9399479144449 |
| 17 | 22568149425822049 |
| 18 | 1293753708921104809 |
| 19 | 2835106739783283 |
| 20 | 3289668853728536041 |
[1,3,25,147,1089,20449,48841,312987,55190041, 14322675,100100025,32065374675,4546130625, 29873533563,1859904071089,4089135109921, 9399479144449,22568149425822049, 1293753708921104809,2835106739783283, 3289668853728536041] |