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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 5 |
| 3 | 16 |
| 4 | 50 |
| 5 | 147 |
| 6 | 422 |
| 7 | 1210 |
| 8 | 3459 |
| 9 | 9878 |
| 10 | 28189 |
| 11 | 80425 |
| 12 | 229411 |
| 13 | 654311 |
| 14 | 1866003 |
| 15 | 5321194 |
| 16 | 15173321 |
| 17 | 43264523 |
| 18 | 123357771 |
| 19 | 351712022 |
| 20 | 1002758190 |
| 21 | 2858875748 |
| 22 | 8150529454 |
| 23 | 23236408366 |
| 24 | 66243882238 |
| 25 | 188849982251 |
| 26 | 538372895393 |
| 27 | 1534776215805 |
| 28 | 4375251800924 |
[1,5,16,50,147,422,1210,3459,9878,28189,80425, 229411,654311,1866003,5321194,15173321,43264523, 123357771,351712022,1002758190,2858875748, 8150529454,23236408366,66243882238,188849982251, 538372895393,1534776215805,4375251800924] |