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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 15 |
| 5 | 52 |
| 6 | 151 |
| 7 | 409 |
| 8 | 1100 |
| 9 | 3012 |
| 10 | 8487 |
| 11 | 23949 |
| 12 | 67179 |
| 13 | 187431 |
| 14 | 521889 |
| 15 | 1455667 |
| 16 | 4066220 |
| 17 | 11363476 |
| 18 | 31747666 |
| 19 | 88659265 |
| 20 | 247559056 |
| 21 | 691294366 |
| 22 | 1930595096 |
| 23 | 5391864630 |
| 24 | 15058449487 |
| 25 | 42054270461 |
| 26 | 117445036871 |
| 27 | 327989716409 |
| 28 | 915985822220 |
| 29 | 2558107420307 |
[1,1,2,5,15,52,151,409,1100,3012,8487,23949,67179, 187431,521889,1455667,4066220,11363476,31747666, 88659265,247559056,691294366,1930595096, 5391864630,15058449487,42054270461,117445036871, 327989716409,915985822220,2558107420307] |