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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 26 |
| 4 | 103 |
| 5 | 431 |
| 6 | 1855 |
| 7 | 8162 |
| 8 | 36536 |
| 9 | 165906 |
| 10 | 761186 |
| 11 | 3523172 |
| 12 | 16431550 |
| 13 | 77110432 |
| 14 | 363762487 |
| 15 | 1723943613 |
| 16 | 8203032788 |
| 17 | 39167716373 |
| 18 | 187591916040 |
| 19 | 900940280855 |
| 20 | 4337494011557 |
| 21 | 20928059000850 |
| 22 | 101176329599767 |
| 23 | 490014622802161 |
| 24 | 2377084688453104 |
| 25 | 11548470442268891 |
| 26 | 56181879040517649 |
| 27 | 273659651846794425 |
[1,2,7,26,103,431,1855,8162,36536,165906,761186, 3523172,16431550,77110432,363762487,1723943613, 8203032788,39167716373,187591916040,900940280855, 4337494011557,20928059000850,101176329599767, 490014622802161,2377084688453104, 11548470442268891,56181879040517649, 273659651846794425] |