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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 6 |
| 5 | 32 |
| 6 | 186 |
| 7 | 1245 |
| 8 | 9588 |
| 9 | 83752 |
| 10 | 817980 |
| 11 | 8827745 |
| 12 | 104277450 |
| 13 | 1337781336 |
| 14 | 18518728326 |
| 15 | 275087536717 |
| 16 | 4364152920456 |
| 17 | 73637731186160 |
| 18 | 1316713607842968 |
| 19 | 24869730218182497 |
| 20 | 494752411594456110 |
| 21 | 10339913354716379440 |
| 22 | 226485946787802241650 |
| 23 | 5188447062121251600221 |
[0,0,1,6,32,186,1245,9588,83752,817980,8827745, 104277450,1337781336,18518728326,275087536717, 4364152920456,73637731186160,1316713607842968, 24869730218182497,494752411594456110, 10339913354716379440,226485946787802241650, 5188447062121251600221] |