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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 9 |
| 3 | 24 |
| 4 | 59 |
| 5 | 138 |
| 6 | 313 |
| 7 | 697 |
| 8 | 1536 |
| 9 | 3364 |
| 10 | 7333 |
| 11 | 15910 |
| 12 | 34341 |
| 13 | 73714 |
| 14 | 157349 |
| 15 | 334099 |
| 16 | 705986 |
| 17 | 1485532 |
| 18 | 3114529 |
| 19 | 6509784 |
| 20 | 13571007 |
| 21 | 28229371 |
| 22 | 58610200 |
| 23 | 121489570 |
| 24 | 251470489 |
| 25 | 519863440 |
| 26 | 1073511567 |
| 27 | 2214592484 |
| 28 | 4564586763 |
| 29 | 9401093855 |
[1,3,9,24,59,138,313,697,1536,3364,7333,15910, 34341,73714,157349,334099,705986,1485532,3114529, 6509784,13571007,28229371,58610200,121489570, 251470489,519863440,1073511567,2214592484, 4564586763,9401093855] |