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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 11 |
| 4 | 42 |
| 5 | 151 |
| 6 | 597 |
| 7 | 2378 |
| 8 | 9788 |
| 9 | 40882 |
| 10 | 173588 |
| 11 | 745698 |
| 12 | 3237487 |
| 13 | 14175810 |
| 14 | 62544126 |
| 15 | 277703191 |
| 16 | 1240091242 |
| 17 | 5564821058 |
| 18 | 25082363701 |
| 19 | 113493074323 |
| 20 | 515341994973 |
| 21 | 2347383158755 |
| 22 | 10722871159531 |
| 23 | 49108802008133 |
| 24 | 225440567737862 |
| 25 | 1037148875601554 |
| 26 | 4780909060419277 |
| 27 | 22078621364281286 |
[1,1,4,11,42,151,597,2378,9788,40882,173588, 745698,3237487,14175810,62544126,277703191, 1240091242,5564821058,25082363701,113493074323, 515341994973,2347383158755,10722871159531, 49108802008133,225440567737862,1037148875601554, 4780909060419277,22078621364281286] |