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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 6 |
| 3 | 15 |
| 4 | 105 |
| 5 | 110 |
| 6 | 2145 |
| 7 | 935 |
| 8 | 3553 |
| 9 | 163438 |
| 10 | 618222 |
| 11 | 1681130 |
| 12 | 1314610 |
| 13 | 7478810 |
| 14 | 56528230 |
| 15 | 2533253470 |
| 16 | 872029246 |
| 17 | 84271102135 |
| 18 | 459400861870 |
| 19 | 58425959482 |
| 20 | 247074041822 |
| 21 | 949284476474 |
| 22 | 327711206734538 |
| 23 | 1447872915170 |
| 24 | 11714608131830 |
| 25 | 12499486876662610 |
| 26 | 63324881704174 |
[2,6,15,105,110,2145,935,3553,163438,618222, 1681130,1314610,7478810,56528230,2533253470, 872029246,84271102135,459400861870,58425959482, 247074041822,949284476474,327711206734538, 1447872915170,11714608131830,12499486876662610, 63324881704174] |