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| n | a(n) |
|---|---|
| 1 | 11 |
| 2 | 53 |
| 3 | 255 |
| 4 | 1231 |
| 5 | 5943 |
| 6 | 28695 |
| 7 | 138551 |
| 8 | 668983 |
| 9 | 3230135 |
| 10 | 15596471 |
| 11 | 75306423 |
| 12 | 363611575 |
| 13 | 1755671991 |
| 14 | 8477134263 |
| 15 | 40931225015 |
| 16 | 197633437111 |
| 17 | 954258648503 |
| 18 | 4607568342455 |
| 19 | 22247307963831 |
| 20 | 107419505225143 |
| 21 | 518667252755895 |
| 22 | 2504347031924151 |
| 23 | 12092057138720183 |
[11,53,255,1231,5943,28695,138551,668983,3230135, 15596471,75306423,363611575,1755671991,8477134263, 40931225015,197633437111,954258648503, 4607568342455,22247307963831,107419505225143, 518667252755895,2504347031924151, 12092057138720183] |