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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 2 |
| 5 | 5 |
| 6 | 14 |
| 7 | 39 |
| 8 | 117 |
| 9 | 353 |
| 10 | 1099 |
| 11 | 3458 |
| 12 | 11066 |
| 13 | 35738 |
| 14 | 116622 |
| 15 | 383448 |
| 16 | 1269869 |
| 17 | 4230557 |
| 18 | 14170956 |
| 19 | 47693457 |
| 20 | 161207066 |
| 21 | 546987882 |
| 22 | 1862464911 |
| 23 | 6361729689 |
| 24 | 21793247587 |
| 25 | 74855427331 |
| 26 | 257743707769 |
| 27 | 889477338903 |
| 28 | 3076038022778 |
| 29 | 10658447368514 |
| 30 | 36998473045302 |
[1,0,1,2,5,14,39,117,353,1099,3458,11066,35738, 116622,383448,1269869,4230557,14170956,47693457, 161207066,546987882,1862464911,6361729689, 21793247587,74855427331,257743707769,889477338903, 3076038022778,10658447368514,36998473045302] |