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| n | a(n) |
|---|---|
| 1 | 7 |
| 2 | 26 |
| 3 | 156 |
| 4 | 692 |
| 5 | 3580 |
| 6 | 17742 |
| 7 | 88056 |
| 8 | 439338 |
| 9 | 2192602 |
| 10 | 10912392 |
| 11 | 54394628 |
| 12 | 271160024 |
| 13 | 1351103246 |
| 14 | 6733077562 |
| 15 | 33557756016 |
| 16 | 167232569172 |
| 17 | 833404135538 |
| 18 | 4153405692526 |
| 19 | 20698773896328 |
| 20 | 103153449929238 |
| 21 | 514074952403758 |
[7,26,156,692,3580,17742,88056,439338,2192602, 10912392,54394628,271160024,1351103246,6733077562, 33557756016,167232569172,833404135538, 4153405692526,20698773896328,103153449929238, 514074952403758] |