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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 21 |
| 5 | 73 |
| 6 | 229 |
| 7 | 634 |
| 8 | 1562 |
| 9 | 3481 |
| 10 | 7132 |
| 11 | 13622 |
| 12 | 24531 |
| 13 | 42033 |
| 14 | 69031 |
| 15 | 109306 |
| 16 | 167680 |
| 17 | 250193 |
| 18 | 364294 |
| 19 | 519046 |
| 20 | 725345 |
| 21 | 996153 |
| 22 | 1346745 |
| 23 | 1794970 |
| 24 | 2361526 |
| 25 | 3070249 |
| 26 | 3948416 |
| 27 | 5027062 |
| 28 | 6341311 |
| 29 | 7930721 |
| 30 | 9839643 |
[1,2,6,21,73,229,634,1562,3481,7132,13622,24531, 42033,69031,109306,167680,250193,364294,519046, 725345,996153,1346745,1794970,2361526,3070249, 3948416,5027062,6341311,7930721,9839643] |