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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 6 |
| 3 | 17 |
| 4 | 43 |
| 5 | 114 |
| 6 | 297 |
| 7 | 779 |
| 8 | 2038 |
| 9 | 5337 |
| 10 | 13971 |
| 11 | 36578 |
| 12 | 95761 |
| 13 | 250707 |
| 14 | 656358 |
| 15 | 1718369 |
| 16 | 4498747 |
| 17 | 11777874 |
| 18 | 30834873 |
| 19 | 80726747 |
| 20 | 211345366 |
| 21 | 553309353 |
| 22 | 1448582691 |
| 23 | 3792438722 |
| 24 | 9928733473 |
| 25 | 25993761699 |
| 26 | 68052551622 |
| 27 | 178163893169 |
[1,3,6,17,43,114,297,779,2038,5337,13971,36578, 95761,250707,656358,1718369,4498747,11777874, 30834873,80726747,211345366,553309353,1448582691, 3792438722,9928733473,25993761699,68052551622, 178163893169] |