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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 3 |
| 3 | 10 |
| 4 | 30 |
| 5 | 82 |
| 6 | 226 |
| 7 | 615 |
| 8 | 1673 |
| 9 | 4549 |
| 10 | 12366 |
| 11 | 33616 |
| 12 | 91379 |
| 13 | 248396 |
| 14 | 675213 |
| 15 | 1835420 |
| 16 | 4989190 |
| 17 | 13562026 |
| 18 | 36865411 |
| 19 | 100210580 |
| 20 | 272400599 |
| 21 | 740461600 |
| 22 | 2012783314 |
| 23 | 5471312309 |
| 24 | 14872568830 |
| 25 | 40427833595 |
| 26 | 109894245428 |
[0,3,10,30,82,226,615,1673,4549,12366,33616,91379, 248396,675213,1835420,4989190,13562026,36865411, 100210580,272400599,740461600,2012783314, 5471312309,14872568830,40427833595,109894245428] |