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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 0 |
| 4 | 2 |
| 5 | 6 |
| 6 | 0 |
| 7 | 184 |
| 8 | 936 |
| 9 | 6688 |
| 10 | 0 |
| 11 | 420480 |
| 12 | 4298664 |
| 13 | 44405142 |
| 14 | 0 |
| 15 | 6732621476 |
| 16 | 92014579912 |
| 17 | 1345077232898 |
| 18 | 0 |
| 19 | 349174373111790 |
| 20 | 6179276762966832 |
| 21 | 114913276077265202 |
| 22 | 0 |
[1,0,0,2,6,0,184,936,6688,0,420480,4298664, 44405142,0,6732621476,92014579912,1345077232898,0, 349174373111790,6179276762966832, 114913276077265202,0] |