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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 24 |
| 5 | 165 |
| 6 | 1202 |
| 7 | 12663 |
| 8 | 149744 |
| 9 | 1945065 |
| 10 | 29307362 |
| 11 | 489387723 |
| 12 | 8915702664 |
| 13 | 178036818765 |
| 14 | 3852374482322 |
| 15 | 89628609049983 |
| 16 | 2235770536642784 |
| 17 | 59498096957789265 |
| 18 | 1681835781220294082 |
[0,1,2,3,24,165,1202,12663,149744,1945065, 29307362,489387723,8915702664,178036818765, 3852374482322,89628609049983,2235770536642784, 59498096957789265,1681835781220294082] |