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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 13 |
| 5 | 34 |
| 6 | 90 |
| 7 | 239 |
| 8 | 635 |
| 9 | 1689 |
| 10 | 4494 |
| 11 | 11960 |
| 12 | 31832 |
| 13 | 84727 |
| 14 | 225524 |
| 15 | 600302 |
| 16 | 1597904 |
| 17 | 4253371 |
| 18 | 11321838 |
| 19 | 30137079 |
| 20 | 80220557 |
| 21 | 213535632 |
| 22 | 568401380 |
| 23 | 1513003529 |
[1,2,5,13,34,90,239,635,1689,4494,11960,31832, 84727,225524,600302,1597904,4253371,11321838, 30137079,80220557,213535632,568401380,1513003529] |