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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 11 |
| 5 | 30 |
| 6 | 95 |
| 7 | 298 |
| 8 | 1006 |
| 9 | 3389 |
| 10 | 11909 |
| 11 | 41892 |
| 12 | 151248 |
| 13 | 547242 |
| 14 | 2013692 |
| 15 | 7428090 |
| 16 | 27714657 |
| 17 | 103659360 |
| 18 | 390818670 |
| 19 | 1476869632 |
| 20 | 5613303220 |
| 21 | 21379805046 |
| 22 | 81781927372 |
| 23 | 313417411878 |
| 24 | 1205079525721 |
| 25 | 4641169988978 |
| 26 | 17920658283987 |
| 27 | 69296999144435 |
| 28 | 268512038320354 |
| 29 | 1041768167687090 |
| 30 | 4048556883494679 |
[1,1,2,4,11,30,95,298,1006,3389,11909,41892, 151248,547242,2013692,7428090,27714657,103659360, 390818670,1476869632,5613303220,21379805046, 81781927372,313417411878,1205079525721, 4641169988978,17920658283987,69296999144435, 268512038320354,1041768167687090,4048556883494679] |