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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 6 |
| 3 | 25 |
| 4 | 92 |
| 5 | 317 |
| 6 | 1054 |
| 7 | 3425 |
| 8 | 10964 |
| 9 | 34729 |
| 10 | 109162 |
| 11 | 341125 |
| 12 | 1061132 |
| 13 | 3288713 |
| 14 | 10161666 |
| 15 | 31318201 |
| 16 | 96312696 |
| 17 | 295632805 |
| 18 | 905955146 |
| 19 | 2772234385 |
| 20 | 8472129040 |
| 21 | 25861509393 |
| 22 | 78861419302 |
| 23 | 240252829461 |
| 24 | 731313754312 |
| 25 | 2224352781697 |
[0,1,6,25,92,317,1054,3425,10964,34729,109162, 341125,1061132,3288713,10161666,31318201,96312696, 295632805,905955146,2772234385,8472129040, 25861509393,78861419302,240252829461,731313754312, 2224352781697] |