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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 23 |
| 4 | 96 |
| 5 | 354 |
| 6 | 1558 |
| 7 | 6126 |
| 8 | 27515 |
| 9 | 112507 |
| 10 | 512529 |
| 11 | 2147588 |
| 12 | 9885539 |
| 13 | 42148934 |
| 14 | 195391127 |
| 15 | 844315803 |
| 16 | 3934322576 |
| 17 | 17179647304 |
| 18 | 80384018006 |
| 19 | 353955909902 |
| 20 | 1661689382158 |
| 21 | 7367702237571 |
| 22 | 34682335239711 |
| 23 | 154675340648931 |
| 24 | 729757290756506 |
| 25 | 3270774292939276 |
| 26 | 15461202200359990 |
| 27 | 69595681801664499 |
[1,2,7,23,96,354,1558,6126,27515,112507,512529, 2147588,9885539,42148934,195391127,844315803, 3934322576,17179647304,80384018006,353955909902, 1661689382158,7367702237571,34682335239711, 154675340648931,729757290756506,3270774292939276, 15461202200359990,69595681801664499] |