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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 15 |
| 5 | 50 |
| 6 | 178 |
| 7 | 663 |
| 8 | 2553 |
| 9 | 10086 |
| 10 | 40669 |
| 11 | 166752 |
| 12 | 693331 |
| 13 | 2917088 |
| 14 | 12398545 |
| 15 | 53164201 |
| 16 | 229729439 |
| 17 | 999460624 |
| 18 | 4374546305 |
| 19 | 19250233408 |
| 20 | 85120272755 |
| 21 | 378021050306 |
| 22 | 1685406494673 |
| 23 | 7541226435054 |
| 24 | 33852474532769 |
| 25 | 152415463629568 |
| 26 | 688099122024944 |
[1,2,5,15,50,178,663,2553,10086,40669,166752, 693331,2917088,12398545,53164201,229729439, 999460624,4374546305,19250233408,85120272755, 378021050306,1685406494673,7541226435054, 33852474532769,152415463629568,688099122024944] |