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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 10 |
| 5 | 60 |
| 6 | 304 |
| 7 | 1420 |
| 8 | 6312 |
| 9 | 27167 |
| 10 | 114412 |
| 11 | 474563 |
| 12 | 1947098 |
| 13 | 7925708 |
| 14 | 32072580 |
| 15 | 129213082 |
| 16 | 518818124 |
| 17 | 2077775396 |
| 18 | 8304424080 |
| 19 | 33138971978 |
| 20 | 132078954532 |
| 21 | 525904271587 |
| 22 | 2092410377864 |
| 23 | 8320012474033 |
| 24 | 33066905278394 |
| 25 | 131371155380369 |
[0,0,1,10,60,304,1420,6312,27167,114412,474563, 1947098,7925708,32072580,129213082,518818124, 2077775396,8304424080,33138971978,132078954532, 525904271587,2092410377864,8320012474033, 33066905278394,131371155380369] |