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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 2 |
| 2 | 7 |
| 3 | 26 |
| 4 | 97 |
| 5 | 366 |
| 6 | 1388 |
| 7 | 5288 |
| 8 | 20225 |
| 9 | 77618 |
| 10 | 298766 |
| 11 | 1153018 |
| 12 | 4460072 |
| 13 | 17287558 |
| 14 | 67129566 |
| 15 | 261095420 |
| 16 | 1016994627 |
| 17 | 3966529870 |
| 18 | 15488964428 |
| 19 | 60549061804 |
| 20 | 236932924494 |
| 21 | 927984726826 |
| 22 | 3637661249946 |
| 23 | 14270586372348 |
| 24 | 56024073085546 |
| 25 | 220089137078792 |
| 26 | 865154426179408 |
| 27 | 3402841810234762 |
| 28 | 13391422390407194 |
[0,2,7,26,97,366,1388,5288,20225,77618,298766, 1153018,4460072,17287558,67129566,261095420, 1016994627,3966529870,15488964428,60549061804, 236932924494,927984726826,3637661249946, 14270586372348,56024073085546,220089137078792, 865154426179408,3402841810234762, 13391422390407194] |