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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 9 |
| 3 | 36 |
| 4 | 155 |
| 5 | 711 |
| 6 | 3252 |
| 7 | 14987 |
| 8 | 71034 |
| 9 | 335301 |
| 10 | 1590682 |
| 11 | 7638914 |
| 12 | 36642619 |
| 13 | 176197696 |
| 14 | 853153680 |
| 15 | 4128974864 |
| 16 | 20015103523 |
| 17 | 97433641619 |
| 18 | 474259672053 |
| 19 | 2311057339844 |
| 20 | 11293164676456 |
| 21 | 55188713180901 |
| 22 | 269929241371606 |
| 23 | 1322783339929551 |
| 24 | 6483263066793933 |
| 25 | 31796814951934582 |
| 26 | 156163700094061499 |
[1,2,9,36,155,711,3252,14987,71034,335301,1590682, 7638914,36642619,176197696,853153680,4128974864, 20015103523,97433641619,474259672053, 2311057339844,11293164676456,55188713180901, 269929241371606,1322783339929551,6483263066793933, 31796814951934582,156163700094061499] |