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| n | a(n) |
|---|---|
| 4 | 1 |
| 5 | 1 |
| 6 | 3 |
| 7 | 10 |
| 8 | 27 |
| 9 | 79 |
| 10 | 234 |
| 11 | 686 |
| 12 | 2036 |
| 13 | 6080 |
| 14 | 18224 |
| 15 | 54920 |
| 16 | 166245 |
| 17 | 505201 |
| 18 | 1541014 |
| 19 | 4716540 |
| 20 | 14480699 |
| 21 | 44586619 |
| 22 | 137648341 |
| 23 | 425992838 |
| 24 | 1321362034 |
| 25 | 4107332002 |
| 26 | 12792440104 |
| 27 | 39915889304 |
| 28 | 124762916912 |
| 29 | 390594099694 |
| 30 | 1224682772872 |
| 31 | 3845389399882 |
[1,1,3,10,27,79,234,686,2036,6080,18224,54920, 166245,505201,1541014,4716540,14480699,44586619, 137648341,425992838,1321362034,4107332002, 12792440104,39915889304,124762916912,390594099694, 1224682772872,3845389399882] |