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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 3528 |
| 3 | 0 |
| 4 | 2076816 |
| 5 | 0 |
| 6 | 490681688 |
| 7 | 0 |
| 8 | 62456027424 |
| 9 | 0 |
| 10 | 4985149915368 |
| 11 | 0 |
| 12 | 273998113272240 |
| 13 | 0 |
| 14 | 11053262513080440 |
| 15 | 0 |
| 16 | 342841481215636032 |
| 17 | 0 |
| 18 | 8471578904288191496 |
| 19 | 0 |
| 20 | 171504713146698879696 |
| 21 | 2199023255552 |
[1,0,3528,0,2076816,0,490681688,0,62456027424,0, 4985149915368,0,273998113272240,0, 11053262513080440,0,342841481215636032,0, 8471578904288191496,0,171504713146698879696, 2199023255552] |