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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 0 |
| 3 | 15 |
| 4 | 110 |
| 5 | 1095 |
| 6 | 10326 |
| 7 | 107056 |
| 8 | 1149126 |
| 9 | 12845166 |
| 10 | 147817170 |
| 11 | 1743640902 |
| 12 | 20987930112 |
| 13 | 256987965373 |
| 14 | 3192889862238 |
| 15 | 40171643818920 |
| 16 | 510996955110550 |
| 17 | 6563060603543652 |
| 18 | 85017386945583408 |
| 19 | 1109744672540225361 |
| 20 | 14585261031466256370 |
| 21 | 192882251992018723947 |
[1,1,0,15,110,1095,10326,107056,1149126,12845166, 147817170,1743640902,20987930112,256987965373, 3192889862238,40171643818920,510996955110550, 6563060603543652,85017386945583408, 1109744672540225361,14585261031466256370, 192882251992018723947] |