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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 576 |
| 5 | 21076 |
| 6 | 296296 |
| 7 | 2475473 |
| 8 | 14739153 |
| 9 | 68943381 |
| 10 | 268880381 |
| 11 | 909450751 |
| 12 | 2742417535 |
| 13 | 7522650135 |
| 14 | 19058554515 |
| 15 | 45123156390 |
| 16 | 100771975590 |
| 17 | 213877057086 |
| 18 | 434042943246 |
| 19 | 846542846578 |
| 20 | 1593528150578 |
[0,0,0,0,576,21076,296296,2475473,14739153, 68943381,268880381,909450751,2742417535, 7522650135,19058554515,45123156390,100771975590, 213877057086,434042943246,846542846578, 1593528150578] |