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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 3 |
| 5 | 11 |
| 6 | 62 |
| 7 | 510 |
| 8 | 7459 |
| 9 | 197867 |
| 10 | 9808968 |
| 11 | 902893994 |
| 12 | 153723380584 |
| 13 | 48443158427276 |
| 14 | 28363698856991892 |
| 15 | 30996526139142442460 |
| 16 | 63502034434187094606966 |
| 17 | 244852545450108200518282934 |
| 18 | 1783161611521019613186341526720 |
| 19 | 24603891216946828886755056314074748 |
[1,0,0,1,3,11,62,510,7459,197867,9808968, 902893994,153723380584,48443158427276, 28363698856991892,30996526139142442460, 63502034434187094606966, 244852545450108200518282934, 1783161611521019613186341526720, 24603891216946828886755056314074748] |