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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 30 |
| 3 | 150 |
| 4 | 750 |
| 5 | 3750 |
| 6 | 18750 |
| 7 | 93750 |
| 8 | 468750 |
| 9 | 2343750 |
| 10 | 11718750 |
| 11 | 58593750 |
| 12 | 292968750 |
| 13 | 1464843750 |
| 14 | 7324218735 |
| 15 | 36621093600 |
| 16 | 183105467640 |
| 17 | 915527336400 |
| 18 | 4577636673000 |
| 19 | 22888183320000 |
| 20 | 114440916375000 |
| 21 | 572204580750000 |
[1,6,30,150,750,3750,18750,93750,468750,2343750, 11718750,58593750,292968750,1464843750,7324218735, 36621093600,183105467640,915527336400, 4577636673000,22888183320000,114440916375000, 572204580750000] |