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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 16 |
| 4 | 56 |
| 5 | 204 |
| 6 | 780 |
| 7 | 3099 |
| 8 | 12594 |
| 9 | 52123 |
| 10 | 219696 |
| 11 | 939511 |
| 12 | 4061334 |
| 13 | 17733255 |
| 14 | 78151761 |
| 15 | 347048149 |
| 16 | 1551225434 |
| 17 | 6976462330 |
| 18 | 31550130733 |
| 19 | 143365879422 |
| 20 | 654323444492 |
| 21 | 2998603009552 |
| 22 | 13792688901614 |
| 23 | 63654344411450 |
| 24 | 294688265919191 |
| 25 | 1368229743361834 |
| 26 | 6369561861745394 |
| 27 | 29725712375089444 |
[1,2,5,16,56,204,780,3099,12594,52123,219696, 939511,4061334,17733255,78151761,347048149, 1551225434,6976462330,31550130733,143365879422, 654323444492,2998603009552,13792688901614, 63654344411450,294688265919191,1368229743361834, 6369561861745394,29725712375089444] |