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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 6 |
| 3 | 33 |
| 4 | 180 |
| 5 | 985 |
| 6 | 5418 |
| 7 | 29953 |
| 8 | 166344 |
| 9 | 927441 |
| 10 | 5188590 |
| 11 | 29113953 |
| 12 | 163786428 |
| 13 | 923511849 |
| 14 | 5217709266 |
| 15 | 29532022785 |
| 16 | 167417253648 |
| 17 | 950453221153 |
| 18 | 5402869685334 |
| 19 | 30748881013153 |
| 20 | 175186193208900 |
| 21 | 999071379620601 |
| 22 | 5702750629608186 |
| 23 | 32578618535692033 |
| 24 | 186257611786501080 |
[0,1,6,33,180,985,5418,29953,166344,927441, 5188590,29113953,163786428,923511849,5217709266, 29532022785,167417253648,950453221153, 5402869685334,30748881013153,175186193208900, 999071379620601,5702750629608186, 32578618535692033,186257611786501080] |