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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 17 |
| 4 | 60 |
| 5 | 221 |
| 6 | 842 |
| 7 | 3268 |
| 8 | 12943 |
| 9 | 52388 |
| 10 | 214155 |
| 11 | 884488 |
| 12 | 3686528 |
| 13 | 15470371 |
| 14 | 65441142 |
| 15 | 278518297 |
| 16 | 1191216971 |
| 17 | 5119104161 |
| 18 | 22089151177 |
| 19 | 95691982593 |
| 20 | 416093182339 |
| 21 | 1814989333091 |
| 22 | 7939913073542 |
| 23 | 34828221815934 |
| 24 | 153156480769247 |
| 25 | 675125047994678 |
| 26 | 2982561230246697 |
| 27 | 13202839750340194 |
[1,2,5,17,60,221,842,3268,12943,52388,214155, 884488,3686528,15470371,65441142,278518297, 1191216971,5119104161,22089151177,95691982593, 416093182339,1814989333091,7939913073542, 34828221815934,153156480769247,675125047994678, 2982561230246697,13202839750340194] |