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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 13 |
| 3 | 37 |
| 4 | 205 |
| 5 | 793 |
| 6 | 3673 |
| 7 | 15481 |
| 8 | 68485 |
| 9 | 295453 |
| 10 | 1291237 |
| 11 | 5605489 |
| 12 | 24418801 |
| 13 | 106183729 |
| 14 | 462160957 |
| 15 | 2010578005 |
| 16 | 8748949309 |
| 17 | 38065839625 |
| 18 | 165631750345 |
| 19 | 720670846249 |
| 20 | 3135725035573 |
| 21 | 13643790283981 |
| 22 | 59365501769941 |
[1,13,37,205,793,3673,15481,68485,295453,1291237, 5605489,24418801,106183729,462160957,2010578005, 8748949309,38065839625,165631750345,720670846249, 3135725035573,13643790283981,59365501769941] |