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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 3 |
| 3 | 8 |
| 4 | 23 |
| 5 | 67 |
| 6 | 200 |
| 7 | 597 |
| 8 | 1790 |
| 9 | 5369 |
| 10 | 16105 |
| 11 | 48314 |
| 12 | 144939 |
| 13 | 434816 |
| 14 | 1304447 |
| 15 | 3913339 |
| 16 | 11740016 |
| 17 | 35220045 |
| 18 | 105660134 |
| 19 | 316980401 |
| 20 | 950941201 |
| 21 | 2852823602 |
| 22 | 8558470803 |
| 23 | 25675412408 |
| 24 | 77026237223 |
| 25 | 231078711667 |
| 26 | 693236135000 |
| 27 | 2079708404997 |
[2,3,8,23,67,200,597,1790,5369,16105,48314,144939, 434816,1304447,3913339,11740016,35220045, 105660134,316980401,950941201,2852823602, 8558470803,25675412408,77026237223,231078711667, 693236135000,2079708404997] |