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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 6 |
| 3 | 180 |
| 4 | 540 |
| 5 | 2856 |
| 6 | 5544 |
| 7 | 16830 |
| 8 | 27060 |
| 9 | 62244 |
| 10 | 90090 |
| 11 | 175440 |
| 12 | 237456 |
| 13 | 413820 |
| 14 | 534660 |
| 15 | 860706 |
| 16 | 1074744 |
| 17 | 1630200 |
| 18 | 1983150 |
| 19 | 2872044 |
| 20 | 3422580 |
| 21 | 4776480 |
| 22 | 5597856 |
| 23 | 7579110 |
| 24 | 8760780 |
| 25 | 11565756 |
| 26 | 13214994 |
| 27 | 17077320 |
| 28 | 19320840 |
| 29 | 24514644 |
| 30 | 27500220 |
| 31 | 34343370 |
| 32 | 38241456 |
| 33 | 47098800 |
[0,6,180,540,2856,5544,16830,27060,62244,90090, 175440,237456,413820,534660,860706,1074744, 1630200,1983150,2872044,3422580,4776480,5597856, 7579110,8760780,11565756,13214994,17077320, 19320840,24514644,27500220,34343370,38241456, 47098800] |