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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 3 |
| 3 | 7 |
| 4 | 13 |
| 5 | 53 |
| 6 | 211 |
| 7 | 2111 |
| 8 | 8443 |
| 9 | 33773 |
| 10 | 202637 |
| 11 | 1621097 |
| 12 | 16210969 |
| 13 | 453907133 |
| 14 | 8170328393 |
| 15 | 196087881433 |
| 16 | 1176527288597 |
| 17 | 7059163731583 |
| 18 | 254129894336987 |
| 19 | 6099117464087689 |
| 20 | 158577054066279913 |
| 21 | 8246006811446555477 |
[2,3,7,13,53,211,2111,8443,33773,202637,1621097, 16210969,453907133,8170328393,196087881433, 1176527288597,7059163731583,254129894336987, 6099117464087689,158577054066279913, 8246006811446555477] |