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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 17 |
| 4 | 69 |
| 5 | 249 |
| 6 | 1117 |
| 7 | 4529 |
| 8 | 19893 |
| 9 | 82313 |
| 10 | 373677 |
| 11 | 1609825 |
| 12 | 7263205 |
| 13 | 31601529 |
| 14 | 144929117 |
| 15 | 643356881 |
| 16 | 2943504405 |
| 17 | 13142716521 |
| 18 | 60720099853 |
| 19 | 274355968577 |
| 20 | 1266272052037 |
| 21 | 5743409115225 |
| 22 | 26680362529213 |
| 23 | 121961107159217 |
| 24 | 566334183070581 |
| 25 | 2595856470100297 |
| 26 | 12109569624436333 |
| 27 | 55810461563660321 |
[1,1,5,17,69,249,1117,4529,19893,82313,373677, 1609825,7263205,31601529,144929117,643356881, 2943504405,13142716521,60720099853,274355968577, 1266272052037,5743409115225,26680362529213, 121961107159217,566334183070581,2595856470100297, 12109569624436333,55810461563660321] |