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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 1 |
| 7 | 3 |
| 8 | 27 |
| 9 | 171 |
| 10 | 1249 |
| 11 | 8389 |
| 12 | 56078 |
| 13 | 360430 |
| 14 | 2272598 |
| 15 | 14037552 |
| 16 | 85516427 |
| 17 | 514976658 |
| 18 | 3074986236 |
| 19 | 18239677629 |
| 20 | 107654218055 |
| 21 | 632996894925 |
| 22 | 3711499485032 |
| 23 | 21716765203045 |
| 24 | 126880009551584 |
[0,0,0,0,0,1,3,27,171,1249,8389,56078,360430, 2272598,14037552,85516427,514976658,3074986236, 18239677629,107654218055,632996894925, 3711499485032,21716765203045,126880009551584] |