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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 10 |
| 4 | 27 |
| 5 | 72 |
| 6 | 179 |
| 7 | 447 |
| 8 | 1139 |
| 9 | 2912 |
| 10 | 7434 |
| 11 | 18949 |
| 12 | 48256 |
| 13 | 122905 |
| 14 | 313153 |
| 15 | 797993 |
| 16 | 2033404 |
| 17 | 5181138 |
| 18 | 13201355 |
| 19 | 33636776 |
| 20 | 85706587 |
| 21 | 218381247 |
| 22 | 556436971 |
| 23 | 1417803304 |
| 24 | 3612566114 |
| 25 | 9204828661 |
| 26 | 23453934912 |
| 27 | 59760710321 |
| 28 | 152270499073 |
[1,4,10,27,72,179,447,1139,2912,7434,18949,48256, 122905,313153,797993,2033404,5181138,13201355, 33636776,85706587,218381247,556436971,1417803304, 3612566114,9204828661,23453934912,59760710321, 152270499073] |