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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 9 |
| 3 | 58 |
| 4 | 401 |
| 5 | 2952 |
| 6 | 22759 |
| 7 | 181358 |
| 8 | 1481751 |
| 9 | 12346102 |
| 10 | 104505959 |
| 11 | 896170608 |
| 12 | 7768885801 |
| 13 | 67972510202 |
| 14 | 599449125609 |
| 15 | 5323095489058 |
| 16 | 47555513297801 |
| 17 | 427127946025752 |
| 18 | 3854618439044959 |
| 19 | 34934658168463958 |
| 20 | 317834095671077751 |
| 21 | 2901725605879035502 |
| 22 | 26575914921615695759 |
[1,2,9,58,401,2952,22759,181358,1481751,12346102, 104505959,896170608,7768885801,67972510202, 599449125609,5323095489058,47555513297801, 427127946025752,3854618439044959, 34934658168463958,317834095671077751, 2901725605879035502,26575914921615695759] |