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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 17 |
| 4 | 60 |
| 5 | 221 |
| 6 | 842 |
| 7 | 3296 |
| 8 | 13055 |
| 9 | 52736 |
| 10 | 215995 |
| 11 | 892130 |
| 12 | 3721084 |
| 13 | 15641114 |
| 14 | 66149907 |
| 15 | 281448936 |
| 16 | 1204203656 |
| 17 | 5175356782 |
| 18 | 22336615979 |
| 19 | 96782596868 |
| 20 | 420774787816 |
| 21 | 1835193720702 |
| 22 | 8028162116450 |
| 23 | 35214500581325 |
| 24 | 154849465504524 |
| 25 | 682526378223530 |
| 26 | 3014873000908227 |
| 27 | 13344302448375870 |
[1,2,5,17,60,221,842,3296,13055,52736,215995, 892130,3721084,15641114,66149907,281448936, 1204203656,5175356782,22336615979,96782596868, 420774787816,1835193720702,8028162116450, 35214500581325,154849465504524,682526378223530, 3014873000908227,13344302448375870] |