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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 23 |
| 4 | 79 |
| 5 | 274 |
| 6 | 1003 |
| 7 | 3763 |
| 8 | 14723 |
| 9 | 59663 |
| 10 | 250738 |
| 11 | 1090608 |
| 12 | 4905430 |
| 13 | 22777420 |
| 14 | 109040012 |
| 15 | 537401702 |
| 16 | 2723210617 |
| 17 | 14170838544 |
| 18 | 75639280146 |
| 19 | 413692111521 |
| 20 | 2316122210804 |
| 21 | 13261980807830 |
| 22 | 77598959094772 |
| 23 | 463626704130058 |
| 24 | 2826406013488180 |
| 25 | 17569700716557737 |
[1,2,7,23,79,274,1003,3763,14723,59663,250738, 1090608,4905430,22777420,109040012,537401702, 2723210617,14170838544,75639280146,413692111521, 2316122210804,13261980807830,77598959094772, 463626704130058,2826406013488180, 17569700716557737] |