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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 21 |
| 3 | 157 |
| 4 | 1239 |
| 5 | 10047 |
| 6 | 82951 |
| 7 | 693603 |
| 8 | 5854581 |
| 9 | 49778997 |
| 10 | 425712429 |
| 11 | 3657968097 |
| 12 | 31555053921 |
| 13 | 273109567797 |
| 14 | 2370474720369 |
| 15 | 20625186298269 |
| 16 | 179841473895447 |
| 17 | 1571088267426447 |
| 18 | 13747953837604959 |
| 19 | 120482775658910763 |
| 20 | 1057293764707074027 |
| 21 | 9289536349244758791 |
| 22 | 81709329486947791419 |
[1,3,21,157,1239,10047,82951,693603,5854581, 49778997,425712429,3657968097,31555053921, 273109567797,2370474720369,20625186298269, 179841473895447,1571088267426447, 13747953837604959,120482775658910763, 1057293764707074027,9289536349244758791, 81709329486947791419] |