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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 26 |
| 3 | 254 |
| 4 | 1554 |
| 5 | 10734 |
| 6 | 78660 |
| 7 | 560942 |
| 8 | 3987615 |
| 9 | 28515358 |
| 10 | 203892406 |
| 11 | 1456644769 |
| 12 | 10408749868 |
| 13 | 74388848144 |
| 14 | 531625780268 |
| 15 | 3799304215218 |
| 16 | 27152396258135 |
| 17 | 194049997801018 |
| 18 | 1386817640950191 |
| 19 | 9911186585406690 |
| 20 | 70832453927754955 |
[1,26,254,1554,10734,78660,560942,3987615, 28515358,203892406,1456644769,10408749868, 74388848144,531625780268,3799304215218, 27152396258135,194049997801018,1386817640950191, 9911186585406690,70832453927754955] |