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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 13 |
| 3 | 1027 |
| 4 | 52741 |
| 5 | 468481 |
| 6 | 2890927 |
| 7 | 4166539 |
| 8 | 37009999 |
| 9 | 228383233 |
| 10 | 999884119 |
| 11 | 1345997497 |
| 12 | 1900627417 |
| 13 | 2126334691 |
| 14 | 4499474941 |
| 15 | 5037873529 |
| 16 | 11728490839 |
| 17 | 104180336299 |
| 18 | 105897267463 |
| 19 | 150149565943 |
| 20 | 926550776281 |
| 21 | 4056529870783 |
[1,13,1027,52741,468481,2890927,4166539,37009999, 228383233,999884119,1345997497,1900627417, 2126334691,4499474941,5037873529,11728490839, 104180336299,105897267463,150149565943, 926550776281,4056529870783] |