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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 6 |
| 3 | 29 |
| 4 | 209 |
| 5 | 1652 |
| 6 | 15981 |
| 7 | 171837 |
| 8 | 2060481 |
| 9 | 26951143 |
| 10 | 381398614 |
| 11 | 5789262973 |
| 12 | 93674732887 |
| 13 | 1607249998772 |
| 14 | 29114205685585 |
| 15 | 554699253112833 |
| 16 | 11079840198856480 |
| 17 | 231366880421810416 |
| 18 | 5038182952520057443 |
| 19 | 114152394913959017721 |
| 20 | 2685768694808159100283 |
[1,6,29,209,1652,15981,171837,2060481,26951143, 381398614,5789262973,93674732887,1607249998772, 29114205685585,554699253112833,11079840198856480, 231366880421810416,5038182952520057443, 114152394913959017721,2685768694808159100283] |