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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 9 |
| 3 | 24 |
| 4 | 63 |
| 5 | 162 |
| 6 | 414 |
| 7 | 1053 |
| 8 | 2673 |
| 9 | 6777 |
| 10 | 17172 |
| 11 | 43497 |
| 12 | 110160 |
| 13 | 278964 |
| 14 | 706401 |
| 15 | 1788723 |
| 16 | 4529277 |
| 17 | 11468628 |
| 18 | 29039715 |
| 19 | 73531314 |
| 20 | 186188058 |
| 21 | 471445029 |
| 22 | 1193741145 |
| 23 | 3022659261 |
| 24 | 7653642696 |
| 25 | 19379704653 |
| 26 | 49071136176 |
| 27 | 124252480440 |
[1,3,9,24,63,162,414,1053,2673,6777,17172,43497, 110160,278964,706401,1788723,4529277,11468628, 29039715,73531314,186188058,471445029,1193741145, 3022659261,7653642696,19379704653,49071136176, 124252480440] |