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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 22 |
| 4 | 92 |
| 5 | 420 |
| 6 | 2034 |
| 7 | 10262 |
| 8 | 53330 |
| 9 | 283410 |
| 10 | 1532698 |
| 11 | 8406698 |
| 12 | 46650072 |
| 13 | 261416000 |
| 14 | 1477208374 |
| 15 | 8407900890 |
| 16 | 48158339716 |
| 17 | 277375020772 |
| 18 | 1605477915982 |
| 19 | 9333727605762 |
| 20 | 54478721494436 |
| 21 | 319120526072380 |
| 22 | 1875410643820166 |
| 23 | 11054224586789010 |
| 24 | 65334486288626586 |
| 25 | 387118590382759994 |
[1,2,6,22,92,420,2034,10262,53330,283410,1532698, 8406698,46650072,261416000,1477208374,8407900890, 48158339716,277375020772,1605477915982, 9333727605762,54478721494436,319120526072380, 1875410643820166,11054224586789010, 65334486288626586,387118590382759994] |