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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 7 |
| 4 | 30 |
| 5 | 69 |
| 6 | 293 |
| 7 | 809 |
| 8 | 3382 |
| 9 | 10439 |
| 10 | 43701 |
| 11 | 143573 |
| 12 | 607068 |
| 13 | 2074221 |
| 14 | 8852116 |
| 15 | 31177563 |
| 16 | 133899322 |
| 17 | 483528703 |
| 18 | 2086264777 |
| 19 | 7687404457 |
| 20 | 33298955306 |
| 21 | 124729199423 |
| 22 | 542093742204 |
| 23 | 2058678763143 |
| 24 | 8972283179552 |
| 25 | 34477413838191 |
| 26 | 150612967540901 |
| 27 | 584671713820833 |
| 28 | 2559233654640368 |
[1,1,4,7,30,69,293,809,3382,10439,43701,143573, 607068,2074221,8852116,31177563,133899322, 483528703,2086264777,7687404457,33298955306, 124729199423,542093742204,2058678763143, 8972283179552,34477413838191,150612967540901, 584671713820833,2559233654640368] |