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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 26 |
| 4 | 118 |
| 5 | 438 |
| 6 | 2068 |
| 7 | 8166 |
| 8 | 39240 |
| 9 | 160688 |
| 10 | 780200 |
| 11 | 3273018 |
| 12 | 15999030 |
| 13 | 68284180 |
| 14 | 335314092 |
| 15 | 1449775962 |
| 16 | 7142547625 |
| 17 | 31195747268 |
| 18 | 154066314055 |
| 19 | 678400361461 |
| 20 | 3356698148209 |
| 21 | 14880029141896 |
| 22 | 73734216202712 |
| 23 | 328704931071284 |
| 24 | 1630735149455340 |
| 25 | 7304765510790510 |
| 26 | 36274431142871498 |
| 27 | 163164514434486246 |
[1,2,8,26,118,438,2068,8166,39240,160688,780200, 3273018,15999030,68284180,335314092,1449775962, 7142547625,31195747268,154066314055,678400361461, 3356698148209,14880029141896,73734216202712, 328704931071284,1630735149455340,7304765510790510, 36274431142871498,163164514434486246] |