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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 9 |
| 5 | 20 |
| 6 | 49 |
| 7 | 117 |
| 8 | 297 |
| 9 | 746 |
| 10 | 1947 |
| 11 | 5021 |
| 12 | 13378 |
| 13 | 35237 |
| 14 | 95123 |
| 15 | 254825 |
| 16 | 694987 |
| 17 | 1882707 |
| 18 | 5184391 |
| 19 | 14177587 |
| 20 | 39289183 |
| 21 | 108337723 |
| 22 | 301997384 |
| 23 | 837774846 |
| 24 | 2347293253 |
| 25 | 6546903307 |
| 26 | 18417850843 |
| 27 | 51617715836 |
| 28 | 145722478875 |
| 29 | 409964137081 |
| 30 | 1161300892672 |
[1,1,2,4,9,20,49,117,297,746,1947,5021,13378, 35237,95123,254825,694987,1882707,5184391, 14177587,39289183,108337723,301997384,837774846, 2347293253,6546903307,18417850843,51617715836, 145722478875,409964137081,1161300892672] |