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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 21 |
| 4 | 65 |
| 5 | 194 |
| 6 | 573 |
| 7 | 1668 |
| 8 | 4809 |
| 9 | 13745 |
| 10 | 39011 |
| 11 | 110052 |
| 12 | 308857 |
| 13 | 862886 |
| 14 | 2401195 |
| 15 | 6658509 |
| 16 | 18406373 |
| 17 | 50738918 |
| 18 | 139513269 |
| 19 | 382731240 |
| 20 | 1047768621 |
| 21 | 2862908777 |
| 22 | 7808872007 |
| 23 | 21265115976 |
| 24 | 57822787825 |
| 25 | 157010774474 |
| 26 | 425795804623 |
[1,2,7,21,65,194,573,1668,4809,13745,39011,110052, 308857,862886,2401195,6658509,18406373,50738918, 139513269,382731240,1047768621,2862908777, 7808872007,21265115976,57822787825,157010774474, 425795804623] |