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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 21 |
| 4 | 82 |
| 5 | 282 |
| 6 | 1198 |
| 7 | 4466 |
| 8 | 19705 |
| 9 | 76858 |
| 10 | 347131 |
| 11 | 1397815 |
| 12 | 6429031 |
| 13 | 26498484 |
| 14 | 123329949 |
| 15 | 517100523 |
| 16 | 2429332648 |
| 17 | 10327174912 |
| 18 | 48879963250 |
| 19 | 210096616126 |
| 20 | 1000125434896 |
| 21 | 4337820817891 |
| 22 | 20749634479045 |
| 23 | 90690386324898 |
| 24 | 435549017087419 |
| 25 | 1916054338405430 |
| 26 | 9232861896129354 |
| 27 | 40845399173564374 |
[1,2,7,21,82,282,1198,4466,19705,76858,347131, 1397815,6429031,26498484,123329949,517100523, 2429332648,10327174912,48879963250,210096616126, 1000125434896,4337820817891,20749634479045, 90690386324898,435549017087419,1916054338405430, 9232861896129354,40845399173564374] |