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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 7 |
| 5 | 16 |
| 6 | 42 |
| 7 | 109 |
| 8 | 289 |
| 9 | 787 |
| 10 | 2162 |
| 11 | 6013 |
| 12 | 16901 |
| 13 | 47872 |
| 14 | 136602 |
| 15 | 392275 |
| 16 | 1132674 |
| 17 | 3286790 |
| 18 | 9579725 |
| 19 | 28031888 |
| 20 | 82320819 |
| 21 | 242538673 |
| 22 | 716708853 |
| 23 | 2123672215 |
| 24 | 6308410522 |
| 25 | 18782623833 |
| 26 | 56043067377 |
| 27 | 167552256398 |
| 28 | 501859077675 |
| 29 | 1505784274718 |
| 30 | 4525272671985 |
[1,1,1,3,7,16,42,109,289,787,2162,6013,16901, 47872,136602,392275,1132674,3286790,9579725, 28031888,82320819,242538673,716708853,2123672215, 6308410522,18782623833,56043067377,167552256398, 501859077675,1505784274718,4525272671985] |