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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 5 |
| 6 | 21 |
| 7 | 83 |
| 8 | 385 |
| 9 | 2131 |
| 10 | 24025 |
| 11 | 318135 |
| 12 | 5078109 |
| 13 | 98561015 |
| 14 | 2403657061 |
| 15 | 86079554793 |
| 16 | 4029871316637 |
| 17 | 240018399697859 |
| 18 | 18147620162041911 |
| 19 | 1762019890516576641 |
| 20 | 229246937643264356069 |
| 21 | 39291648711744977550585 |
[1,1,1,1,5,21,83,385,2131,24025,318135,5078109, 98561015,2403657061,86079554793,4029871316637, 240018399697859,18147620162041911, 1762019890516576641,229246937643264356069, 39291648711744977550585] |