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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 7 |
| 2 | 13 |
| 3 | 73 |
| 4 | 325 |
| 5 | 1837 |
| 6 | 10117 |
| 7 | 59725 |
| 8 | 356293 |
| 9 | 2185597 |
| 10 | 13583269 |
| 11 | 85698973 |
| 12 | 546399109 |
| 13 | 3518219773 |
| 14 | 22835491813 |
| 15 | 149279803741 |
| 16 | 981896308165 |
| 17 | 6493968318781 |
| 18 | 43158035158309 |
| 19 | 288073454728861 |
| 20 | 1930386933091333 |
[1,7,13,73,325,1837,10117,59725,356293,2185597, 13583269,85698973,546399109,3518219773, 22835491813,149279803741,981896308165, 6493968318781,43158035158309,288073454728861, 1930386933091333] |