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| n | a(n) |
|---|---|
| 1 | 8 |
| 2 | 18 |
| 3 | 38 |
| 4 | 84 |
| 5 | 180 |
| 6 | 394 |
| 7 | 850 |
| 8 | 1852 |
| 9 | 4008 |
| 10 | 8714 |
| 11 | 18886 |
| 12 | 41020 |
| 13 | 88964 |
| 14 | 193138 |
| 15 | 419010 |
| 16 | 909460 |
| 17 | 1973352 |
| 18 | 4282722 |
| 19 | 9293318 |
| 20 | 20168132 |
| 21 | 43765364 |
| 22 | 94976442 |
| 23 | 206104402 |
| 24 | 447268364 |
| 25 | 970605128 |
| 26 | 2106305818 |
| 27 | 4570852838 |
| 28 | 9919165164 |
| 29 | 21525417860 |
[8,18,38,84,180,394,850,1852,4008,8714,18886, 41020,88964,193138,419010,909460,1973352,4282722, 9293318,20168132,43765364,94976442,206104402, 447268364,970605128,2106305818,4570852838, 9919165164,21525417860] |