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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 2 |
| 3 | 4 |
| 4 | 6 |
| 5 | 14 |
| 6 | 27 |
| 7 | 80 |
| 8 | 210 |
| 9 | 805 |
| 10 | 2370 |
| 11 | 12127 |
| 12 | 45783 |
| 13 | 276334 |
| 14 | 1343098 |
| 15 | 10464249 |
| 16 | 60421447 |
| 17 | 607880695 |
| 18 | 4555562667 |
| 19 | 54131941863 |
| 20 | 525633914241 |
| 21 | 8090369486591 |
| 22 | 92774939175347 |
| 23 | 1849817523944554 |
| 24 | 27457199067870165 |
| 25 | 646952049880982614 |
[1,2,2,4,6,14,27,80,210,805,2370,12127,45783, 276334,1343098,10464249,60421447,607880695, 4555562667,54131941863,525633914241,8090369486591, 92774939175347,1849817523944554,27457199067870165, 646952049880982614] |