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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 10 |
| 5 | 74 |
| 6 | 504 |
| 7 | 3383 |
| 8 | 23004 |
| 9 | 160444 |
| 10 | 1154524 |
| 11 | 8594072 |
| 12 | 66243532 |
| 13 | 528776232 |
| 14 | 4369175522 |
| 15 | 37343891839 |
| 16 | 329883579768 |
| 17 | 3008985817304 |
| 18 | 28312886239136 |
| 19 | 274561779926323 |
| 20 | 2741471453779930 |
| 21 | 28159405527279326 |
| 22 | 297291626845716642 |
| 23 | 3223299667111201702 |
[0,0,0,1,10,74,504,3383,23004,160444,1154524, 8594072,66243532,528776232,4369175522,37343891839, 329883579768,3008985817304,28312886239136, 274561779926323,2741471453779930, 28159405527279326,297291626845716642, 3223299667111201702] |