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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 18 |
| 4 | 72 |
| 5 | 310 |
| 6 | 1399 |
| 7 | 6532 |
| 8 | 31287 |
| 9 | 152876 |
| 10 | 759034 |
| 11 | 3818410 |
| 12 | 19420713 |
| 13 | 99697784 |
| 14 | 515909606 |
| 15 | 2688267462 |
| 16 | 14093211259 |
| 17 | 74281217492 |
| 18 | 393389969722 |
| 19 | 2092312452404 |
| 20 | 11171325560120 |
| 21 | 59854910468196 |
| 22 | 321717833732186 |
| 23 | 1734250394445622 |
| 24 | 9373581927760595 |
[1,2,5,18,72,310,1399,6532,31287,152876,759034, 3818410,19420713,99697784,515909606,2688267462, 14093211259,74281217492,393389969722, 2092312452404,11171325560120,59854910468196, 321717833732186,1734250394445622,9373581927760595] |