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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 12 |
| 4 | 780 |
| 5 | 16286 |
| 6 | 159452 |
| 7 | 992412 |
| 8 | 4567836 |
| 9 | 16959488 |
| 10 | 53617596 |
| 11 | 149618794 |
| 12 | 377841356 |
| 13 | 879314442 |
| 14 | 1911495356 |
| 15 | 3922051616 |
| 16 | 7657895196 |
| 17 | 14321764860 |
| 18 | 25791609308 |
| 19 | 44921419134 |
| 20 | 75946019596 |
| 21 | 125016699158 |
| 22 | 200899440924 |
| 23 | 315872975684 |
| 24 | 486869916572 |
| 25 | 736910896536 |
[0,0,12,780,16286,159452,992412,4567836,16959488, 53617596,149618794,377841356,879314442,1911495356, 3922051616,7657895196,14321764860,25791609308, 44921419134,75946019596,125016699158,200899440924, 315872975684,486869916572,736910896536] |