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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 13 |
| 3 | 65 |
| 4 | 403 |
| 5 | 2669 |
| 6 | 18759 |
| 7 | 136477 |
| 8 | 1020373 |
| 9 | 7785741 |
| 10 | 60395165 |
| 11 | 474817833 |
| 12 | 3775005799 |
| 13 | 30298719855 |
| 14 | 245167429681 |
| 15 | 1997854542163 |
| 16 | 16381233095985 |
| 17 | 135050690760831 |
| 18 | 1118800428892925 |
| 19 | 9308791880014333 |
| 20 | 77755512086256649 |
[1,3,13,65,403,2669,18759,136477,1020373,7785741, 60395165,474817833,3775005799,30298719855, 245167429681,1997854542163,16381233095985, 135050690760831,1118800428892925,9308791880014333, 77755512086256649] |