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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 12 |
| 4 | 124 |
| 5 | 1844 |
| 6 | 39288 |
| 7 | 1134928 |
| 8 | 42346256 |
| 9 | 1985443536 |
| 10 | 114380311072 |
| 11 | 7938644848832 |
| 12 | 653292526793664 |
| 13 | 62901472582993984 |
| 14 | 7005466255571255168 |
| 15 | 893590563265303934208 |
| 16 | 129425758313629525647616 |
| 17 | 21124489015640181154724096 |
| 18 | 3859303832272520341300756992 |
[1,1,2,12,124,1844,39288,1134928,42346256, 1985443536,114380311072,7938644848832, 653292526793664,62901472582993984, 7005466255571255168,893590563265303934208, 129425758313629525647616, 21124489015640181154724096, 3859303832272520341300756992] |