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| n | a(n) |
|---|---|
| 1 | 6 |
| 2 | 32 |
| 3 | 150 |
| 4 | 690 |
| 5 | 3311 |
| 6 | 16968 |
| 7 | 93103 |
| 8 | 544920 |
| 9 | 3386262 |
| 10 | 22243902 |
| 11 | 153850981 |
| 12 | 1116625523 |
| 13 | 8478969009 |
| 14 | 67185160511 |
| 15 | 554235206898 |
| 16 | 4750165417926 |
| 17 | 42219358673456 |
| 18 | 388485398829204 |
| 19 | 3695187060252009 |
| 20 | 36282147267628868 |
[6,32,150,690,3311,16968,93103,544920,3386262, 22243902,153850981,1116625523,8478969009, 67185160511,554235206898,4750165417926, 42219358673456,388485398829204,3695187060252009, 36282147267628868] |