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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 11 |
| 5 | 29 |
| 6 | 85 |
| 7 | 281 |
| 8 | 1003 |
| 9 | 3764 |
| 10 | 14811 |
| 11 | 61327 |
| 12 | 267153 |
| 13 | 1219497 |
| 14 | 5807473 |
| 15 | 28763988 |
| 16 | 147898511 |
| 17 | 788330533 |
| 18 | 4349414397 |
| 19 | 24799271517 |
| 20 | 145904796179 |
| 21 | 884577652276 |
| 22 | 5519858796807 |
| 23 | 35415056743815 |
| 24 | 233393746525705 |
| 25 | 1578437838849645 |
| 26 | 10945142365689985 |
| 27 | 77752626344174676 |
[1,1,1,4,11,29,85,281,1003,3764,14811,61327, 267153,1219497,5807473,28763988,147898511, 788330533,4349414397,24799271517,145904796179, 884577652276,5519858796807,35415056743815, 233393746525705,1578437838849645, 10945142365689985,77752626344174676] |