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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 22 |
| 5 | 87 |
| 6 | 348 |
| 7 | 1374 |
| 8 | 5335 |
| 9 | 20462 |
| 10 | 77988 |
| 11 | 296787 |
| 12 | 1130969 |
| 13 | 4321239 |
| 14 | 16559467 |
| 15 | 63633036 |
| 16 | 245113705 |
| 17 | 946140207 |
| 18 | 3658715938 |
| 19 | 14170931497 |
| 20 | 54966429252 |
| 21 | 213487762758 |
| 22 | 830195102515 |
| 23 | 3232062132146 |
| 24 | 12596093756080 |
| 25 | 49137833964185 |
| 26 | 191862494482159 |
[1,1,2,6,22,87,348,1374,5335,20462,77988,296787, 1130969,4321239,16559467,63633036,245113705, 946140207,3658715938,14170931497,54966429252, 213487762758,830195102515,3232062132146, 12596093756080,49137833964185,191862494482159] |