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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 15 |
| 4 | 37 |
| 5 | 91 |
| 6 | 225 |
| 7 | 555 |
| 8 | 1368 |
| 9 | 3375 |
| 10 | 8323 |
| 11 | 20527 |
| 12 | 50625 |
| 13 | 124852 |
| 14 | 307911 |
| 15 | 759375 |
| 16 | 1872780 |
| 17 | 4618672 |
| 18 | 11390625 |
| 19 | 28091697 |
| 20 | 69280082 |
| 21 | 170859375 |
| 22 | 421375454 |
| 23 | 1039201232 |
| 24 | 2562890625 |
| 25 | 6320631805 |
| 26 | 15588018474 |
| 27 | 38443359375 |
| 28 | 94809477068 |
| 29 | 233820277107 |
[1,2,6,15,37,91,225,555,1368,3375,8323,20527, 50625,124852,307911,759375,1872780,4618672, 11390625,28091697,69280082,170859375,421375454, 1039201232,2562890625,6320631805,15588018474, 38443359375,94809477068,233820277107] |