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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 25 |
| 4 | 99 |
| 5 | 405 |
| 6 | 1714 |
| 7 | 7427 |
| 8 | 32737 |
| 9 | 146383 |
| 10 | 661869 |
| 11 | 3020265 |
| 12 | 13889929 |
| 13 | 64291101 |
| 14 | 299260749 |
| 15 | 1399700354 |
| 16 | 6574435846 |
| 17 | 30995358969 |
| 18 | 146611032296 |
| 19 | 695533590390 |
| 20 | 3308404066736 |
| 21 | 15774602645911 |
| 22 | 75377396802039 |
| 23 | 360897351359596 |
| 24 | 1731065825672997 |
| 25 | 8317002690540882 |
| 26 | 40020944485987337 |
| 27 | 192852380846196131 |
[1,2,7,25,99,405,1714,7427,32737,146383,661869, 3020265,13889929,64291101,299260749,1399700354, 6574435846,30995358969,146611032296,695533590390, 3308404066736,15774602645911,75377396802039, 360897351359596,1731065825672997,8317002690540882, 40020944485987337,192852380846196131] |