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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 14 |
| 6 | 41 |
| 7 | 124 |
| 8 | 385 |
| 9 | 1221 |
| 10 | 3939 |
| 11 | 12886 |
| 12 | 42648 |
| 13 | 142544 |
| 14 | 480459 |
| 15 | 1631287 |
| 16 | 5574073 |
| 17 | 19153815 |
| 18 | 66146259 |
| 19 | 229452587 |
| 20 | 799140681 |
| 21 | 2793373937 |
| 22 | 9796395680 |
| 23 | 34459558856 |
| 24 | 121548541383 |
| 25 | 429823475811 |
| 26 | 1523511450184 |
| 27 | 5411789548439 |
[1,1,2,5,14,41,124,385,1221,3939,12886,42648, 142544,480459,1631287,5574073,19153815,66146259, 229452587,799140681,2793373937,9796395680, 34459558856,121548541383,429823475811, 1523511450184,5411789548439] |