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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 2 |
| 6 | 56 |
| 7 | 0 |
| 8 | 4 |
| 9 | 374 |
| 10 | 14980 |
| 11 | 0 |
| 12 | 8 |
| 13 | 2664 |
| 14 | 302844 |
| 15 | 19005336 |
| 16 | 0 |
| 17 | 12 |
| 18 | 17556 |
| 19 | 6530656 |
| 20 | 1248702804 |
| 21 | 278982789260 |
| 22 | 0 |
| 23 | 18 |
| 24 | 121838 |
| 25 | 151793054 |
[0,0,0,0,2,56,0,4,374,14980,0,8,2664,302844, 19005336,0,12,17556,6530656,1248702804, 278982789260,0,18,121838,151793054] |