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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 25 |
| 3 | 30 |
| 4 | 66 |
| 5 | 142 |
| 6 | 289 |
| 7 | 599 |
| 8 | 1268 |
| 9 | 2660 |
| 10 | 5558 |
| 11 | 11659 |
| 12 | 24470 |
| 13 | 51293 |
| 14 | 107533 |
| 15 | 225522 |
| 16 | 472918 |
| 17 | 991618 |
| 18 | 2079349 |
| 19 | 4360310 |
| 20 | 9143205 |
| 21 | 19172527 |
| 22 | 40203428 |
| 23 | 84303632 |
| 24 | 176778210 |
| 25 | 370690543 |
| 26 | 777310342 |
| 27 | 1629961137 |
| 28 | 3417905349 |
| 29 | 7167090042 |
[4,25,30,66,142,289,599,1268,2660,5558,11659, 24470,51293,107533,225522,472918,991618,2079349, 4360310,9143205,19172527,40203428,84303632, 176778210,370690543,777310342,1629961137, 3417905349,7167090042] |