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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 6 |
| 5 | 10 |
| 6 | 28 |
| 7 | 63 |
| 8 | 190 |
| 9 | 546 |
| 10 | 1708 |
| 11 | 5346 |
| 12 | 17428 |
| 13 | 57148 |
| 14 | 191280 |
| 15 | 646363 |
| 16 | 2210670 |
| 17 | 7626166 |
| 18 | 26538292 |
| 19 | 93013854 |
| 20 | 328215300 |
| 21 | 1165060668 |
| 22 | 4158330416 |
| 23 | 14915635378 |
| 24 | 53746119972 |
| 25 | 194477856100 |
| 26 | 706437056648 |
| 27 | 2575316704200 |
| 28 | 9419571138368 |
[1,1,2,3,6,10,28,63,190,546,1708,5346,17428,57148, 191280,646363,2210670,7626166,26538292,93013854, 328215300,1165060668,4158330416,14915635378, 53746119972,194477856100,706437056648, 2575316704200,9419571138368] |