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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 10 |
| 3 | 25 |
| 4 | 71 |
| 5 | 166 |
| 6 | 444 |
| 7 | 1002 |
| 8 | 2601 |
| 9 | 5742 |
| 10 | 14653 |
| 11 | 31864 |
| 12 | 80472 |
| 13 | 173077 |
| 14 | 434243 |
| 15 | 926144 |
| 16 | 2313939 |
| 17 | 4902478 |
| 18 | 12216163 |
| 19 | 25743143 |
| 20 | 64042535 |
| 21 | 134356858 |
| 22 | 333927795 |
| 23 | 697932219 |
| 24 | 1733779702 |
| 25 | 3612110059 |
| 26 | 8971527052 |
| 27 | 18639230426 |
[1,3,10,25,71,166,444,1002,2601,5742,14653,31864, 80472,173077,434243,926144,2313939,4902478, 12216163,25743143,64042535,134356858,333927795, 697932219,1733779702,3612110059,8971527052, 18639230426] |