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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 4 |
| 6 | 8 |
| 7 | 37 |
| 8 | 184 |
| 9 | 1782 |
| 10 | 31026 |
| 11 | 1148626 |
| 12 | 86539128 |
| 13 | 12798435868 |
| 14 | 3620169692289 |
| 15 | 1940367005824561 |
| 16 | 1965937435288738165 |
| 17 | 3766548132138130650270 |
| 18 | 13666503289976224080346733 |
[1,0,1,1,4,8,37,184,1782,31026,1148626,86539128, 12798435868,3620169692289,1940367005824561, 1965937435288738165,3766548132138130650270, 13666503289976224080346733] |