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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 2 |
| 4 | 7 |
| 5 | 24 |
| 6 | 77 |
| 7 | 241 |
| 8 | 738 |
| 9 | 2227 |
| 10 | 6650 |
| 11 | 19711 |
| 12 | 58114 |
| 13 | 170682 |
| 14 | 499911 |
| 15 | 1461284 |
| 16 | 4265437 |
| 17 | 12438449 |
| 18 | 36247956 |
| 19 | 105589899 |
| 20 | 307513742 |
| 21 | 895514715 |
| 22 | 2607925982 |
| 23 | 7595726764 |
| 24 | 22127052759 |
| 25 | 64473303788 |
| 26 | 187912261301 |
| 27 | 547850119836 |
[1,2,7,24,77,241,738,2227,6650,19711,58114,170682, 499911,1461284,4265437,12438449,36247956, 105589899,307513742,895514715,2607925982, 7595726764,22127052759,64473303788,187912261301, 547850119836] |