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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 13 |
| 4 | 60 |
| 5 | 326 |
| 6 | 2065 |
| 7 | 14508 |
| 8 | 116845 |
| 9 | 676579 |
| 10 | 4533285 |
| 11 | 29337447 |
| 12 | 204274255 |
| 13 | 1401597565 |
| 14 | 10464806200 |
| 15 | 75242714351 |
| 16 | 588938921227 |
| 17 | 4060713617519 |
| 18 | 30141138974325 |
| 19 | 217182619165093 |
| 20 | 1630762746458645 |
| 21 | 11987353708674543 |
| 22 | 91946531392941646 |
| 23 | 683807822490949653 |
[1,1,3,13,60,326,2065,14508,116845,676579,4533285, 29337447,204274255,1401597565,10464806200, 75242714351,588938921227,4060713617519, 30141138974325,217182619165093,1630762746458645, 11987353708674543,91946531392941646, 683807822490949653] |