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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 242 |
| 6 | 51504 |
| 7 | 2484382 |
| 8 | 44601420 |
| 9 | 450193818 |
| 10 | 3112919712 |
| 11 | 16471667554 |
| 12 | 71393226972 |
| 13 | 265069706646 |
| 14 | 869583076752 |
| 15 | 2577681275622 |
| 16 | 7020477731884 |
| 17 | 17794428237522 |
| 18 | 42397762374912 |
| 19 | 95726217156906 |
| 20 | 206149749502012 |
| 21 | 425731784898894 |
| 22 | 846919172059632 |
[0,0,0,0,242,51504,2484382,44601420,450193818, 3112919712,16471667554,71393226972,265069706646, 869583076752,2577681275622,7020477731884, 17794428237522,42397762374912,95726217156906, 206149749502012,425731784898894,846919172059632] |