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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 21 |
| 5 | 73 |
| 6 | 223 |
| 7 | 587 |
| 8 | 1356 |
| 9 | 2820 |
| 10 | 5395 |
| 11 | 9653 |
| 12 | 16355 |
| 13 | 26487 |
| 14 | 41299 |
| 15 | 62347 |
| 16 | 91538 |
| 17 | 131178 |
| 18 | 184023 |
| 19 | 253333 |
| 20 | 342929 |
| 21 | 457253 |
| 22 | 601431 |
| 23 | 781339 |
| 24 | 1003672 |
| 25 | 1276016 |
| 26 | 1606923 |
| 27 | 2005989 |
| 28 | 2483935 |
| 29 | 3052691 |
| 30 | 3725483 |
[1,2,6,21,73,223,587,1356,2820,5395,9653,16355, 26487,41299,62347,91538,131178,184023,253333, 342929,457253,601431,781339,1003672,1276016, 1606923,2005989,2483935,3052691,3725483] |