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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 11 |
| 4 | 34 |
| 5 | 93 |
| 6 | 269 |
| 7 | 735 |
| 8 | 2037 |
| 9 | 5515 |
| 10 | 14912 |
| 11 | 39828 |
| 12 | 105931 |
| 13 | 279408 |
| 14 | 733409 |
| 15 | 1913349 |
| 16 | 4968092 |
| 17 | 12835746 |
| 18 | 33020764 |
| 19 | 84586922 |
| 20 | 215844162 |
| 21 | 548725545 |
| 22 | 1390140594 |
| 23 | 3510064528 |
| 24 | 8834980324 |
| 25 | 22171254453 |
| 26 | 55479601543 |
| 27 | 138448505906 |
| 28 | 344594242788 |
| 29 | 855538158016 |
[1,4,11,34,93,269,735,2037,5515,14912,39828, 105931,279408,733409,1913349,4968092,12835746, 33020764,84586922,215844162,548725545,1390140594, 3510064528,8834980324,22171254453,55479601543, 138448505906,344594242788,855538158016] |