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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 10 |
| 4 | 42 |
| 5 | 133 |
| 6 | 583 |
| 7 | 2107 |
| 8 | 9498 |
| 9 | 37100 |
| 10 | 170422 |
| 11 | 700327 |
| 12 | 3260691 |
| 13 | 13885192 |
| 14 | 65303709 |
| 15 | 285469307 |
| 16 | 1353084601 |
| 17 | 6034100741 |
| 18 | 28777781725 |
| 19 | 130354698204 |
| 20 | 624801809350 |
| 21 | 2865740094979 |
| 22 | 13792513955173 |
| 23 | 63908250241073 |
| 24 | 308648304990584 |
| 25 | 1442220043930524 |
| 26 | 6985728178113346 |
| 27 | 32873047087774126 |
[1,1,4,10,42,133,583,2107,9498,37100,170422, 700327,3260691,13885192,65303709,285469307, 1353084601,6034100741,28777781725,130354698204, 624801809350,2865740094979,13792513955173, 63908250241073,308648304990584,1442220043930524, 6985728178113346,32873047087774126] |