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| n | a(n) |
|---|---|
| 1 | 6 |
| 2 | 6 |
| 3 | 12 |
| 4 | 318 |
| 5 | 900 |
| 6 | 4536 |
| 7 | 34782 |
| 8 | 178926 |
| 9 | 1042284 |
| 10 | 6538206 |
| 11 | 38160540 |
| 12 | 227814120 |
| 13 | 1377960126 |
| 14 | 8227422006 |
| 15 | 49321272972 |
| 16 | 296370593598 |
| 17 | 1776644188020 |
| 18 | 10658199015576 |
| 19 | 63967089528222 |
| 20 | 383739633130686 |
| 21 | 2302372435469484 |
[6,6,12,318,900,4536,34782,178926,1042284,6538206, 38160540,227814120,1377960126,8227422006, 49321272972,296370593598,1776644188020, 10658199015576,63967089528222,383739633130686, 2302372435469484] |