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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 7 |
| 4 | 14 |
| 5 | 26 |
| 6 | 59 |
| 7 | 122 |
| 8 | 284 |
| 9 | 647 |
| 10 | 1528 |
| 11 | 3602 |
| 12 | 8679 |
| 13 | 20882 |
| 14 | 50824 |
| 15 | 124055 |
| 16 | 304574 |
| 17 | 750122 |
| 18 | 1855099 |
| 19 | 4600202 |
| 20 | 11442086 |
| 21 | 28527447 |
| 22 | 71292604 |
| 23 | 178526882 |
| 24 | 447919419 |
| 25 | 1125750146 |
| 26 | 2833906684 |
| 27 | 7144450567 |
| 28 | 18036423974 |
[1,2,4,7,14,26,59,122,284,647,1528,3602,8679, 20882,50824,124055,304574,750122,1855099,4600202, 11442086,28527447,71292604,178526882,447919419, 1125750146,2833906684,7144450567,18036423974] |