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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 2 |
| 6 | 8 |
| 7 | 14 |
| 8 | 55 |
| 9 | 121 |
| 10 | 392 |
| 11 | 989 |
| 12 | 2912 |
| 13 | 7797 |
| 14 | 22104 |
| 15 | 60553 |
| 16 | 169289 |
| 17 | 467622 |
| 18 | 1300888 |
| 19 | 3603914 |
| 20 | 10008543 |
| 21 | 27755249 |
| 22 | 77034176 |
| 23 | 213702153 |
| 24 | 593005504 |
| 25 | 1645265209 |
| 26 | 4565154816 |
| 27 | 12666317073 |
| 28 | 35144684065 |
| 29 | 97512548090 |
| 30 | 270561677224 |
[1,0,1,1,2,8,14,55,121,392,989,2912,7797,22104, 60553,169289,467622,1300888,3603914,10008543, 27755249,77034176,213702153,593005504,1645265209, 4565154816,12666317073,35144684065,97512548090, 270561677224] |