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| n | a(n) |
|---|---|
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 1 |
| 7 | 7 |
| 8 | 34 |
| 9 | 143 |
| 10 | 558 |
| 11 | 2083 |
| 12 | 7559 |
| 13 | 26913 |
| 14 | 94547 |
| 15 | 328943 |
| 16 | 1136218 |
| 17 | 3903245 |
| 18 | 13352270 |
| 19 | 45524764 |
| 20 | 154811018 |
| 21 | 525345268 |
| 22 | 1779722313 |
| 23 | 6020903806 |
| 24 | 20346143381 |
| 25 | 68691126090 |
| 26 | 231732871764 |
| 27 | 781268589267 |
| 28 | 2632605033729 |
| 29 | 8867115559325 |
| 30 | 29855369535397 |
[0,0,0,0,1,7,34,143,558,2083,7559,26913,94547, 328943,1136218,3903245,13352270,45524764, 154811018,525345268,1779722313,6020903806, 20346143381,68691126090,231732871764,781268589267, 2632605033729,8867115559325,29855369535397] |