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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 13 |
| 3 | 103 |
| 4 | 823 |
| 5 | 6581 |
| 6 | 52639 |
| 7 | 421103 |
| 8 | 3368809 |
| 9 | 26950453 |
| 10 | 215603623 |
| 11 | 1724828887 |
| 12 | 13798631089 |
| 13 | 110389048703 |
| 14 | 883112389613 |
| 15 | 7064899116901 |
| 16 | 56519192935207 |
| 17 | 452153543481457 |
| 18 | 3617228347851583 |
| 19 | 28937826782812601 |
| 20 | 231502614262500793 |
[2,13,103,823,6581,52639,421103,3368809,26950453, 215603623,1724828887,13798631089,110389048703, 883112389613,7064899116901,56519192935207, 452153543481457,3617228347851583, 28937826782812601,231502614262500793] |