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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 12 |
| 4 | 41 |
| 5 | 134 |
| 6 | 535 |
| 7 | 2100 |
| 8 | 8008 |
| 9 | 31483 |
| 10 | 125405 |
| 11 | 498762 |
| 12 | 1995254 |
| 13 | 8032580 |
| 14 | 32433136 |
| 15 | 131333532 |
| 16 | 533489683 |
| 17 | 2172483451 |
| 18 | 8865550544 |
| 19 | 36251329866 |
| 20 | 148498309280 |
| 21 | 609271648415 |
| 22 | 2503419660325 |
| 23 | 10299986121600 |
| 24 | 42429641658643 |
[1,1,2,12,41,134,535,2100,8008,31483,125405, 498762,1995254,8032580,32433136,131333532, 533489683,2172483451,8865550544,36251329866, 148498309280,609271648415,2503419660325, 10299986121600,42429641658643] |