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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 31 |
| 3 | 133 |
| 4 | 587 |
| 5 | 2531 |
| 6 | 10950 |
| 7 | 47185 |
| 8 | 203704 |
| 9 | 879711 |
| 10 | 3804530 |
| 11 | 16464710 |
| 12 | 71312805 |
| 13 | 309083291 |
| 14 | 1340546867 |
| 15 | 5817555402 |
| 16 | 25258769216 |
| 17 | 109711224970 |
| 18 | 476675868834 |
| 19 | 2071569641859 |
| 20 | 9004430215111 |
| 21 | 39144480326143 |
| 22 | 170184867215647 |
| 23 | 739924236443359 |
| 24 | 3217001700174226 |
[1,6,31,133,587,2531,10950,47185,203704,879711, 3804530,16464710,71312805,309083291,1340546867, 5817555402,25258769216,109711224970,476675868834, 2071569641859,9004430215111,39144480326143, 170184867215647,739924236443359,3217001700174226] |