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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 7 |
| 2 | 42 |
| 3 | 238 |
| 4 | 1316 |
| 5 | 7196 |
| 6 | 39144 |
| 7 | 212408 |
| 8 | 1151248 |
| 9 | 6236272 |
| 10 | 33772704 |
| 11 | 182873824 |
| 12 | 990172736 |
| 13 | 5361148352 |
| 14 | 29026768512 |
| 15 | 157158071168 |
| 16 | 850889810176 |
| 17 | 4606905485056 |
| 18 | 24942786537984 |
| 19 | 135045615513088 |
| 20 | 731165912572928 |
[1,7,42,238,1316,7196,39144,212408,1151248, 6236272,33772704,182873824,990172736,5361148352, 29026768512,157158071168,850889810176, 4606905485056,24942786537984,135045615513088, 731165912572928] |