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| n | a(n) |
|---|---|
| 0 | 6 |
| 1 | 6 |
| 2 | 30 |
| 3 | 330 |
| 4 | 6090 |
| 5 | 153510 |
| 6 | 4652340 |
| 7 | 158459730 |
| 8 | 5854550130 |
| 9 | 229936985850 |
| 10 | 9477338186316 |
| 11 | 406314955623486 |
| 12 | 18001068994899900 |
| 13 | 820015284879972900 |
| 14 | 38258577340819383240 |
| 15 | 1822437624604345219170 |
| 16 | 88405834606456644170370 |
| 17 | 4358080082619077400555090 |
| 18 | 217935771356984568896708700 |
[6,6,30,330,6090,153510,4652340,158459730, 5854550130,229936985850,9477338186316, 406314955623486,18001068994899900, 820015284879972900,38258577340819383240, 1822437624604345219170,88405834606456644170370, 4358080082619077400555090, 217935771356984568896708700] |